氏名

タキザワ ケンジ

滝沢 研二

職名

教授

所属

(創造理工学部)

連絡先

メールアドレス

メールアドレス
Kenji.Takizawa@tafsm.org
メールアドレス(その他)
Kenji.Takizawa@waseda.jp

住所・電話番号・fax番号

住所
〒169-8555東京都 新宿区 大久保3-4-1 早稲田大学西早稲田キャンパス 58号館217室

URL等

WebページURL

http://www.jp.tafsm.org/(lab)

https://scholar.google.com/citations?user=yP6hAUIAAAAJ(Google Scholar)

http://www.researcherid.com/rid/E-2245-2013(Researcher ID)

研究者プロファイリング(Pure)
Scival
研究者番号
60415809
ORCID ID
0000-0003-1172-113X

本属以外の学内所属

兼担

理工学術院(大学院創造理工学研究科)

学内研究所等

アドバンストマルチコアプロセッサ研究所

研究所員 2011年-2014年

燃焼・伝熱工学研究所

研究所員 2015年-2019年

自動車用触媒研究所

研究所員 2015年-2019年

熱エネルギー変換工学・数学融合研究所

研究所員 2017年-

理工学術院総合研究所(理工学研究所)

兼任研究員 2018年-

燃焼・伝熱工学研究所

研究所員 2019年-

自動車用触媒研究所

研究所員 2019年-

フロンティア流体構造連成解析研究所

研究所員 2019年-

アドバンストマルチコアプロセッサ研究所

研究所員 2014年-2019年

アドバンストマルチコアプロセッサ研究所

研究所員 2019年-

学歴・学位

学歴

-2001年 東京工業大学 工学部 機械宇宙工学
-2002年 東京工業大学 総合理工学研究科 創造エネルギー
-2005年 東京工業大学 総合理工学研究科 創造エネルギー

学位

博士(理学) 課程 東京工業大学

所属学協会

Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME Member

Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME Vice-Chair

Journal of Applied Mechanics, ASME Associate Editor

Committee on Fluid-Structure Interaction, Applied Mechanics Division, ASME Chair

受賞

Highly Cited Researcher (Engineering)

2017年11月授与機関:Clarivate Analytics

Computational Mechanics Award

2017年06月授与機関:日本計算力学連合

ナイスステップな研究者2017

2016年12月授与機関:科学技術・学術政策研究所

リサーチフロントアワード

2016年07月授与機関:トムソン・ロイター

Highly Cited Researcher (Engineering)

2016年11月授与機関:Thomson Reuters

文部科学大臣表彰(若手科学者賞)

2015年04月

Waseda Research Award (High-Impact Publication)

2014年12月

日本機械学会計算力学部門業績賞

2014年11月

2013 APACM Young Investigator Award

2013年12月

Thomas J.R. Hughes Young Investigator Award

2012年11月

Young Investigator Award, International Association for Computational Mechanics

2012年07月

Fellow Award, Japan Association for Computational Mechanics

2012年07月

日本計算力学奨励賞

2007年12月

Best Computer Visualization Award, Third Asian-Pacific Congress on Computational Mechanics and Eleventh International Conference on Enhancement and Promotion of Computational Methods in Engineering and Science

2007年12月

第12回 計算工学講演会・ベストペーパーアワード

2007年05月

研究分野

キーワード

流体構造連成、計算力学、宇宙船用パラシュート、心臓血管系解析、流体機械、流体力学

科研費分類

総合理工 / 機械工学 / 流体工学

数物系科学 / 計算科学

論文

New Directions and Challenging Computations in Fluid Dynamics Modeling with Stabilized and Multiscale Methods

Y. Bazilevs, K. Takizawa, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences, published online, DOI: 10.1142/S02182025150200292015年-

DOI

Space--time VMS method for flow computations with slip interfaces (ST-SI)

K. Takizawa, T.E. Tezduyar, H. Mochizuki, H. Hattori, S. Mei, L. Pan, and K. Montel

Mathematical Models and Methods in Applied Sciences, published online, DOI: 10.1142/S02182025154001262015年-

DOI

Multiscale ST Methods for Thermo-Fluid Analysis of a Ground Vehicle and its Tires

K. Takizawa, T.E. Tezduyar, and T. Kuraishi

Mathematical Models and Methods in Applied Sciences, published online, DOI: 10.1142/S02182025154000722015年-

DOI

FSI Modeling of the Orion Spacecraft Drogue Parachutes

K. Takizawa, T.E. Tezduyar, and R. Kolesar

Computational Mechanics55p.1167 - 11792015年-

DOI

Space--Time Computational Analysis of MAV Flapping-Wing Aerodynamics with Wing Clapping

K. Takizawa, T.E. Tezduyar, and A. Buscher

Computational Mechanics55p.1131 - 11412015年-

DOI

Special Methods for Aerodynamic-Moment Calculations from Parachute FSI Modeling

K. Takizawa, T.E. Tezduyar, C. Boswell, Y. Tsutsui, and K. Montel

Computational Mechanics55p.1059 - 10692015年-

DOI

Multiscale Methods for Gore Curvature Calculations from FSI Modeling of Spacecraft Parachutes

K. Takizawa, T.E. Tezduyar, R. Kolesar, C. Boswell, T. Kanai, and K. Montel

Computational Mechanics54p.1461 - 14762014年-

DOI

A variational multiscale method for particle-cloud tracking in turbomachinery flows

A. Corsini, F. Rispoli, A.G. Sheard, K. Takizawa, T.E. Tezduyar, and P. Venturini

Computational Mechanics54p.1191 - 12022014年-

DOI

Coronary arterial dynamics computation with medical-image-based time-dependent anatomical models and element-based zero-stress state estimates

K. Takizawa, R. Torii, H. Takagi, T.E. Tezduyar, and X.Y. Xu

Computational Mechanics54p.1047 - 10532014年-

DOI

FSI Modeling of the Reefed Stages and Disreefing of the Orion Spacecraft Parachutes

K. Takizawa, T.E. Tezduyar, C. Boswell, R. Kolesar, and K. Montel

Computational Mechanics54p.1203 - 12202014年-

DOI

Space--Time Fluid Mechanics Computation of Heart Valve Models

K. Takizawa, T.E. Tezduyar, A Buscher, and S. Asada

Computational Mechanics54p.973 - 9862014年-

DOI

FSI analysis of the blood flow and geometrical characteristics in the thoracic aorta

H. Suito, K. Takizawa, V.Q.H. Huynh, D. Sze, and T. Ueda

Computational Mechanics54p.1035 - 10452014年-

DOI

Computational Engineering Analysis with the New-Generation Space--Time Methods

Computational Mechanics54p.193 - 2112014年-

DOI

Aerodynamic and FSI Analysis of Wind Turbines with the ALE-VMS and ST-VMS Methods

Y. Bazilevs, K. Takizawa, T.E. Tezduyar, M.-C. Hsu, N. Kostov, and S. McIntyre

Archives of Computational Methods in Engineering21p.359 - 3982014年-

DOI

Engineering Analysis and Design with ALE-VMS and Space--Time Methods

K. Takizawa, Y. Bazilevs, T.E. Tezduyar, M.-C. Hsu, O. Oiseth, K.M. Mathisen, N. Kostov, and S. McIntyre

Archives of Computational Methods in Engineering21p.481 - 5082014年-

DOI

ST and ALE-VMS Methods for Patient-Specific Cardiovascular Fluid Mechanics Modeling

K. Takizawa, Y. Bazilevs, T.E. Tezduyar, C.C. Long, A.L. Marsden, and K. Schjodt

Mathematical Models and Methods in Applied Sciences24p.2437 - 24862014年-

DOI

Sequentially-coupled space--time FSI analysis of bio-inspired flapping-wing aerodynamics of an MAV

K. Takizawa, T.E. Tezduyar, and N. Kostov

Computational Mechanics54p.213 - 2332014年-

DOI

Space--Time Interface-Tracking with Topology Change (ST-TC)

K. Takizawa, T.E. Tezduyar, A Buscher, and S. Asada

Computational Mechanics54p.955 - 9712014年-

DOI

Estimation of Element-Based Zero-Stress State for Arterial FSI Computations

K. Takizawa, H. Takagi, T.E. Tezduyar, and R. Torii

Computational Mechanics54p.895 - 9102014年-

DOI

Space--time computation techniques with continuous representation in time (ST-C)

K. Takizawa, and T.E. Tezduyar

Computational Mechanics53p.91 - 992014年-

DOI

Fluid--structure interaction modeling of clusters of spacecraft parachutes with modified geometric porosity

K. Takizawa, T.E. Tezduyar, J. Boben, N. Kostov, C. Boswell, and A. Buscher

Computational Mechanics52p.1351 - 13642013年-

DOI

Space--time VMS computation of wind-turbine rotor and tower aerodynamics

K. Takizawa, T.E. Tezduyar, S. McIntyre, N. Kostov, R. Kolesar, and C. Habluetzel

Computational Mechanics53p.1 - 152014年-

DOI

Bringing them down safely

K. Takizawa, and T.E. Tezduyar

Mechanical Engineering134p.34 - 372012年-

Computer Modeling Techniques for Flapping-Wing Aerodynamics of a Locust

K. Takizawa, B. Henicke, A. Puntel, N. Kostov, and T.E. Tezduyar

Computers & Fluids85p.125 - 1342013年-

DOI

Challenges and Directions in Computational Fluid--Structure Interaction

Y. Bazilevs, K. Takizawa, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences23p.215 - 2212013年-

DOI

Patient-Specific Computational Analysis of the Influence of a Stent on the Unsteady Flow in Cerebral Aneurysms

K. Takizawa, K. Schjodt, A. Puntel, N. Kostov, and T.E. Tezduyar

Computational Mechanics51p.1061 - 10732013年-

DOI

Space--Time VMS Methods for Modeling of Incompressible Flows at High Reynolds Numbers

K. Takizawa, D. Montes, S. McIntyre, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences23p.223 - 2482013年-

DOI

Methods for FSI modeling of spacecraft parachute dynamics and cover separation

K. Takizawa, D. Montes, M. Fritze, S. McIntyre, J. Boben, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences23p.307 - 3382013年-

DOI

Fluid--structure interaction modeling of ringsail parachutes with disreefing and modified geometric porosity

K. Takizawa, M. Fritze, D. Montes, T. Spielman, and T.E. Tezduyar

Computational Mechanics50p.835 - 8542012年-

DOI

Patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent

K. Takizawa, K. Schjodt, A. Puntel, N. Kostov, and T.E. Tezduyar

Computational Mechanics50p.675 - 6862012年-

DOI

Space--time computational analysis of bio-inspired flapping-wing aerodynamics of a micro aerial vehicle

K. Takizawa, N. Kostov, A. Puntel, B. Henicke, and T.E. Tezduyar

Computational Mechanics50p.761 - 7782012年-

DOI

Space--Time Techniques for Computational Aerodynamics Modeling of Flapping Wings of an Actual Locust

K. Takizawa, B. Henicke, A. Puntel, N. Kostov, and T.E. Tezduyar

Computational Mechanics50p.743 - 7602012年-

DOI

ALE-VMS and ST-VMS Methods for Computer Modeling of Wind-Turbine Rotor Aerodynamics and Fluid--Structure Interaction

Y. Bazilevs, M.-C. Hsu, K. Takizawa, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences22p.12300022012年-

DOI

Space--Time Fluid--Structure Interaction Methods

K. Takizawa, and T.E. Tezduyar

Mathematical Models and Methods in Applied Sciences22p.12300012012年-

DOI

Space--Time and ALE-VMS Techniques for Patient-Specific Cardiovascular Fluid--Structure Interaction Modeling

K. Takizawa, Y. Bazilevs, and T.E. Tezduyar

Archives of Computational Methods in Engineering19p.171 - 2252012年-

DOI

Computational Methods for Parachute Fluid--Structure Interactions

K. Takizawa, and T.E. Tezduyar

Archives of Computational Methods in Engineering19p.125 - 1692012年-

DOI

Space--time computational techniques for the aerodynamics of flapping wings

K. Takizawa, B. Henicke, A. Puntel, T. Spielman, and T.E. Tezduyar

Journal of Applied Mechanics79p.0109032012年-

DOI

A comparative study based on patient-specific fluid--structure interaction modeling of cerebral aneurysms

K. Takizawa, T. Brummer, T.E. Tezduyar, and P.R. Chen

Journal of Applied Mechanics79p.0109082012年-

DOI

Fluid--structure interaction modeling of spacecraft parachutes for simulation-based design

K. Takizawa, T. Spielman, C. Moorman, and T.E. Tezduyar

Journal of Applied Mechanics79p.0109072012年-

DOI

A parallel sparse algorithm targeting arterial fluid mechanics computations

M. Manguoglu, K. Takizawa, A.H. Sameh, and T.E. Tezduyar

Computational Mechanics48p.377 - 3842011年-

DOI

Numerical-Performance Studies for the Stabilized Space--Time Computation of Wind-Turbine Rotor Aerodynamics

K. Takizawa, B. Henicke, D. Montes, T.E. Tezduyar, M.-C. Hsu, and Y. Bazilevs

Computational Mechanics48p.647 - 6572011年-

DOI

Space--time FSI modeling and dynamical analysis of spacecraft parachutes and parachute clusters

K. Takizawa, T. Spielman, and T.E. Tezduyar

Computational Mechanics48p.345 - 3642011年-

DOI

Stabilized Space--Time Computation of Wind-Turbine Rotor Aerodynamics

K. Takizawa, B. Henicke, T.E. Tezduyar, M.-C. Hsu, and Y. Bazilevs

Computational Mechanics48p.333 - 3442011年-

DOI

Multiscale Space--Time Fluid--Structure Interaction Techniques

K. Takizawa, and T.E. Tezduyar

Computational Mechanics48p.247 - 2672011年-

DOI

Space--Time Fluid--Structure Interaction Modeling of Patient-Specific Cerebral Aneurysms

T.E. Tezduyar, K. Takizawa, T. Brummer, and P.R. Chen

International Journal for Numerical Methods in Biomedical Engineering27p.1665 - 17102011年-

DOI

Nested and Parallel Sparse Algorithms for Arterial Fluid Mechanics Computations with Boundary Layer Mesh Refinement

M. Manguoglu, K. Takizawa, A.H. Sameh, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids65p.135 - 1492011年-

DOI

3D Simulation of Wind Turbine Rotors at Full Scale. Part I: Geometry Modeling and Aerodynamics

Y. Bazilevs, M.-C. Hsu, I. Akkerman, S. Wright, K. Takizawa, B. Henicke, T. Spielman, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids65p.207 - 2352011年-

DOI

Fluid--Structure Interaction Modeling of Parachute Clusters

K. Takizawa, S. Wright, C. Moorman, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids65p.286 - 3072011年-

DOI

Patient-Specific Arterial Fluid--Structure Interaction Modeling of Cerebral Aneurysms

K. Takizawa, C. Moorman, S. Wright, J. Purdue, T. McPhail, P.R. Chen, J. Warren, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids65p.308 - 3232011年-

DOI

Fluid--Structure Interaction Modeling and Performance Analysis of the Orion Spacecraft Parachutes

K. Takizawa, C. Moorman, S. Wright, T. Spielman, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids65p.271 - 2852011年-

DOI

Space--Time Finite Element Computation of Complex Fluid--Structure Interactions

T.E. Tezduyar, K. Takizawa, C. Moorman, S. Wright, and J. Christopher

International Journal for Numerical Methods in Fluids64p.1201 - 12182010年-

DOI

Wall Shear Stress Calculations in Space--Time Finite Element Computation of Arterial Fluid--Structure Interactions

K. Takizawa, C. Moorman, S. Wright, J. Christopher, and T.E. Tezduyar

Computational Mechanics46p.31 - 412010年-

DOI

Multiscale Sequentially-Coupled Arterial FSI Technique

T.E. Tezduyar, K. Takizawa, C. Moorman, S. Wright, and J. Christopher

Computational Mechanics46p.17 - 292010年-

DOI

Solution of Linear Systems in Arterial Fluid Mechanics Computations with Boundary Layer Mesh Refinement

M. Manguoglu, K. Takizawa, A.H. Sameh, and T.E. Tezduyar

Computational Mechanics46p.83 - 892010年-

DOI

Space--Time Finite Element Computation of Arterial Fluid--Structure Interactions with Patient-Specific Data

K. Takizawa, J. Christopher, T.E. Tezduyar, and S. Sathe

International Journal for Numerical Methods in Biomedical Engineering26p.101 - 1162010年-

DOI

Conservative Form of Interpolated Differential Operator Scheme for Compressible and Incompressible Fluid Dynamics

Y. Imai, T. Aoki, and K. Takizawa

Journal of Computational Physics227p.2263 - 22852008年-

DOI

Ship Hydrodynamics Computations with the CIP Method Based on Adaptive Soroban Grids

K. Takizawa, K. Tanizawa, T. Yabe, and T.E. Tezduyar

International Journal for Numerical Methods in Fluids54p.1011 - 10192007年-

DOI

Computation of Fluid--Solid and Fluid--Fluid Interfaces with the CIP Method Based on Adaptive Soroban Grids --- An Overview

T. Yabe, K. Takizawa, T.E. Tezduyar, and H.-N. Im

International Journal for Numerical Methods in Fluids54p.841 - 8532007年-

DOI

Computation of Free--Surface Flows and Fluid--Object Interactions with the CIP Method Based on Adaptive Meshless Soroban Grids

K. Takizawa, T. Yabe, Y. Tsugawa, T.E. Tezduyar, and H. Mizoe

Computational Mechanics40p.167 - 1832007年-

DOI

Challenge of CIP as a universal solver for solid, liquid and gas

T. Yabe, K. Takizawa, M. Chino, M. Imai, and C.C. Chu

International Journal for Numerical Methods in Fluids47p.655 - 6762005年-

DOI

Simulation and Experiment on Swimming Fish and Skimmer by CIP Method

K. Takizawa, T. Yabe, M. Chino, T. Kawai, K. Wataji, H. Hoshino, and T. Watanabe

Computers & Structures83p.397 - 4082005年-

DOI

Higher-Order Schemes with CIP Method and Adaptive Soroban Grid Towards Mesh-Free Scheme

T. Yabe, H. Mizoe, K. Takizawa, H. Moriki, H. Im, and Y. Ogata

Journal of Computational Physics194p.57 - 772004年-

DOI

A New Paradigm of Computer Graphics by Universal Solver for Solid, Liquid and Gas

T. Yabe, K. Takizawa, F. Xiao, T. Aoki, T. Himeno, T. Takahashi, and A. Kunimatsu

Japan Society of Mechanical Engineers International Journal. Ser. B, Fluids and Thermal Engineering47p.653 - 6632004年-

DOI

Multi-dimensional Semi-Lagrangian Scheme that Guarantees Exact Conservation

K. Takizawa, T. Yabe, and T. Nakamura

Computer Physics Communications148p.137 - 1592002年-

DOI

The Next Generation CIP as a Conservative Semi-Lagrangian Solver for Solid, Liquid and Gas

T. Yabe, Y. Ogata, K. Takizawa, T. Kawai, A. Segawa, and K. Sakurai

Journal of Computational and Applied Mathematics149p.267 - 2772002年-

DOI

Exactly Conservative Semi-Lagrangian Scheme for Multi-dimensional Hyperbolic Equations

T. Nakamura, R. Tanaka, T. Yabe, and K. Takizawa

Journal of Computational Physics174p.171 - 2072001年-

DOI

Main Aspects of the Space--Time Computational FSI Techniques and Examples of Challenging Problems Solved

K. Takizawa, and T.E. Tezduyar

Mechanical Engineering Reviews1p.CM00052014年-

DOI

Computational Engineering Analysis and Design with ALE-VMS and ST Methods

K. Takizawa, Y. Bazilevs, T.E. Tezduyar, M.-C. Hsu, O. Oiseth, K.M. Mathisen, N. Kostov, and S. McIntyre

Numerical Simulations of Coupled Problems in Engineering33p.321 - 3532014年-

DOI

Computational Wind-Turbine Analysis with the ALE-VMS and ST-VMS Methods

Y. Bazilevs, K. Takizawa, T.E. Tezduyar, M.-C. Hsu, N. Kostov, and S. McIntyre

Numerical Simulations of Coupled Problems in Engineering33p.355 - 3862014年-

DOI

Patient-Specific Cardiovascular Fluid Mechanics Analysis with the ST and ALE-VMS Methods

K. Takizawa, Y. Bazilevs, T.E. Tezduyar, C.C. Long, A.L. Marsden, and K. Schjodt

Numerical Simulations of Coupled Problems in Engineering33p.71 - 1022014年-

DOI

Fluid--Structure Interaction Modeling of Patient-Specific Cerebral Aneurysms

K. Takizawa, and T.E. Tezduyar

Visualization and Simulation of Complex Flows in Biomedical Engineering12p.25 - 452014年-

DOI

Patient-Specific Computational Fluid Mechanics of Cerebral Arteries with Aneurysm and Stent

K. Takizawa, K. Schjodt, A. Puntel, N. Kostov, and T.E. Tezduyar

Multiscale Simulations and Mechanics of Biological Materialsp.119 - 1472013年-

Computer Modeling and Analysis of the Orion Spacecraft Parachutes

K. Takizawa, C. Moorman, S. Wright, and T.E. Tezduyar

Fluid--Structure Interaction II -- Modelling, Simulation, Optimization73p.53 - 812010年-

DOI

Multiscale Sequentially-Coupled Arterial Fluid--Structure Interaction (SCAFSI) Technique

T.E. Tezduyar, K. Takizawa, and J. Christopher

International Workshop on Fluid--Structure Interaction --- Theory, Numerics and Applicationsp.231 - 2522009年-

Recent Advances of Multi-phase Flow Computation with the Adaptive Soroban-grid Cubic Interpolated Propagation (CIP) Method

T. Yabe, Y. Ogata, and K. Takizawa

Computational Fluid Dynamics 2006p.29 - 432009年-

DOI

Universal Solver CIP for All Phases of Matter

T. Yabe, K. Takizawa, F. Xiao, and A. Ikebata

Recent Advances in Scientific Computing and Partial Differential Equations330p.203 - 2222003年-

FSI Modeling of Spacecraft Parachute Dynamics and Cover Separation

K. Takizawa, D. Montes, M. Fritze, S. McIntyre, J. Boben, Y. Tsutsui, and T.E. Tezduyar

Extended Abstracts of JSME 25th Computational Mechanics Division Conference2012年-

Effect of Longitudinal Prestress in Arterial FSI

K. Takizawa, H. Takagi, and T.E. Tezduyar

Extended Abstracts of JSME 25th Computational Mechanics Division Conference2012年-

Space--Time Computational FSI Techniques --- Special Technologies

K. Takizawa, and T.E. Tezduyar

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Space--Time Computational FSI Techniques --- Core Technologies

T.E. Tezduyar, and K. Takizawa

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Space--Time Method and Space--Time VMS Technique

K. Takizawa, and T.E. Tezduyar

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Stabilized Formulations --- Special Techniques

T.E. Tezduyar, and K. Takizawa

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

FSI Coupling Techniques

K. Takizawa, and T.E. Tezduyar

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Mesh Update Methods for Flows with Moving Interfaces

T.E. Tezduyar, and K. Takizawa

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Introduction to Computational Fluid Mechanics with Computer-Generated Movies and Pictures

T.E. Tezduyar, and K. Takizawa

Lecture Notes on Finite Elements in Flow Problems --- Basics and Applications2012年-

Dynamical Analysis of Parachute Clusters

K. Takizawa, T. Spielman, and T.E. Tezduyar

Extended Abstracts of JSME-CMD International Computational Mechanics Symposium 20122012年-

Patient-Specific Modeling of Fluid--Structure Interaction and Stenting in Cerebral Arteries with Aneurysm

K. Takizawa, T. Brummer, K. Schjodt, N. Kostov, A. Puntel, H. Takagi, and T.E. Tezduyar

Extended Abstracts of JSME-CMD International Computational Mechanics Symposium 20122012年-

Space-Time Computational Fluid-Structure Interaction Techniques

T.E. Tezduyar, and K. Takizawa

Proceedings of the 19th National Computational Fluid Dynamics Conference2012年-

Space--Time Computational Techniques for the Aerodynamics of Flapping Locust Wings

K. Takizawa, B. Henicke, A. Puntel, N. Kostov, and T.E. Tezduyar

Proceedings of International Workshop on Future of CFD and Aerospace Sciences2012年-

Patient-Specific Modeling of Cerebral Aneurysms with FSI and Stent

K. Takizawa, K. Schjodt, A. Puntel, N. Kostov, H. Takagi, S. Asada, and T.E. Tezduyar

Proceedings of 17th Japan Society of Computational Engineering and Science Conference2012年-

Computational Modeling of Parachute Fluid--Structure Interaction

K. Takizawa, M. Fritze, D. Montes, S. McIntyre, J. Boben, S. Tabata, Y. Tsutsui, and T.E. Tezduyar

Proceedings of 17th Japan Society of Computational Engineering and Science Conference2012年-

FSI Coupling Techniques and Iterative Solution Methods

K. Takizawa, T.E. Tezduyar, and Y. Bazilevs

Lectures on Computational Fluid--Structure Interaction2012年-

Mesh Update Methods for Computation of Flows With Moving Boundaries and Interfaces

T.E. Tezduyar, K. Takizawa, and Y. Bazilevs

Lectures on Computational Fluid--Structure Interaction2012年-

Introductory Computational Structural Mechanics

Y. Bazilevs, K. Takizawa, and T.E. Tezduyar

Lectures on Computational Fluid--Structure Interaction2012年-

Space--Time Method and Space--Time VMS Technique

K. Takizawa, T.E. Tezduyar, and Y. Bazilevs

Lectures on Computational Fluid--Structure Interaction2012年-

ALE Method and ALE-VMS Technique

Y. Bazilevs, K. Takizawa, and T.E. Tezduyar

Lectures on Computational Fluid--Structure Interaction2012年-

Stabilized Formulations in Computational Fluid Mechanics and Fluid--Structure Interaction

T.E. Tezduyar, K. Takizawa, and Y. Bazilevs

Lectures on Computational Fluid--Structure Interaction2012年-

Space--Time Computational FSI Techniques --- Special Technologies

K. Takizawa, and T.E. Tezduyar

Lectures on Computational Fluid--Structure Interaction2012年-

Space--Time Computational FSI Techniques --- Core Technologies

T.E. Tezduyar, and K. Takizawa

Lectures on Computational Fluid--Structure Interaction2012年-

Fluid--Structure Interaction Modeling of Spacecraft Parachutes

T.E. Tezduyar, K. Takizawa, and S. Wright

Extended Abstracts of the 61st National Congress of Theoretical and Applied Mechanics2012年-

Space--Time Formulation of Fully-Coupled Fluid--Object Interaction

K. Takizawa, S. Asada, N. Kostov, and T.E. Tezduyar

Proceedings of the 25th Computational Fluid Dynamics Conference2011年-

Space--Time FSI Computation of Parachute Disreefing

K. Takizawa, M. Fritze, T. Spielman, C. Moorman, S. Tabata, and T.E. Tezduyar

Proceedings of the 25th Computational Fluid Dynamics Conference2011年-

Multiscale Sequentially-Coupled FSI Computation in Parachute Modeling

K. Takizawa, S. Wright, J. Christopher, and T.E. Tezduyar

Structural Membranes 20112011年-

Space--Time FSI Modeling of Ringsail Parachute Clusters

K. Takizawa, T. Spielman, and T.E. Tezduyar

Structural Membranes 20112011年-

Fluid--Structure Interaction Modeling of Ringsail Parachute Clusters

K. Takizawa, T. Spielman, and T.E. Tezduyar

Recent Progress in Fluid Dynamics Research, Proceedings of the Sixth International Conference on Fluid Mechanics2011年-

Space--Time FSI Modeling and Dynamical Analysis of Ringsail Parachute Clusters

K. Takizawa, T. Spielman, and T.E. Tezduyar

Coupled Problems 20112011年-

Multiscale Space--Time Computation Techniques

K. Takizawa, and T.E. Tezduyar

Coupled Problems 20112011年-

Comparative Patient-Specific FSI Modeling of Cerebral Aneurysms

K. Takizawa, T. Brummer, T.E. Tezduyar, and P.R. Chen

Coupled Problems 20112011年-

Soroban-Grid CIP Method for Ocean Research and Ship Design - High Performance Computing with Earth Simulator -

T. Yabe, Y. Ogata, T. Sugimoto, K. Takizawa, and K. Takahashi

Parallel CFD 20092009年-

Novel Solvers for Linear Systems in Computational Fluid Dynamics

M. Manguoglu, K. Takizawa, A.H. Sameh, and T.E. Tezduyar

Marine 20092009年-

Space--Time Finite Element Computation of Complex FSI Problems

T.E. Tezduyar, K. Takizawa, J. Christopher, C. Moorman, and S. Wright

Coupled Problems 20092009年-

Space--Time Finite Element Computation of Arterial FSI with Patient-Specific Data

K. Takizawa, J. Christopher, C. Moorman, J. Martin, J. Purdue, T. McPhail, P.R. Chen, J. Warren, and T.E. Tezduyar

Coupled Problems 20092009年-

Fluid--Structure Interaction Modeling of the Orion Spacecraft Parachutes

K. Takizawa, J. Christopher, C. Moorman, S. Wright, J. Martin, and T.E. Tezduyar

Coupled Problems 20092009年-

Sequentially-Coupled FSI Technique

T.E. Tezduyar, K. Takizawa, and J. Christopher

Marine 20092009年-

Interface Projection Techniques for Complex FSI Problems

T.E. Tezduyar, K. Takizawa, J. Christopher, C. Moorman, and S. Wright

Marine 20092009年-

Modeling of Fluid--Structure Interactions with the Space--Time Finite Elements

T.E. Tezduyar, S. Sathe, M. Schwaab, J. Christopher, J. Crabtree, and J. Pausewang

Flow Simulation with the Finite Element Methodp.215 - 2512008年-

Incompressible Flow Computations with the Multi-Moment and SUPG/PSPG Formulations

K. Takizawa, S. Sathe, and T.E. Tezduyar

Proceedings of the Third Asian-Pacific Congress on Computational Mechanics (CD-ROM)2007年-

Computation of Fluid--Structure Interactions with the CIP Method Based on Adaptive Meshless Soroban Grids

T. Yabe, K. Takizawa, and T.E. Tezduyar

Marine 20072007年-

Computational Ship Hydrodynamics with the CIP Method

K. Takizawa, K. Tanizawa, T. Yabe, and T.E. Tezduyar

Marine 20072007年-

Computational Fluid-Structure Interaction and Flow Simulation

Bazilevs, Yuri;Takizawa, Kenji

COMPUTERS & FLUIDS141p.1 - 12016年-2016年

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ISSN:0045-7930

Space-Time method for flow computations with slip interfaces and topology changes (ST-SI-TC)

Takizawa, Kenji;Tezduyar, Tayfun E.;Asada, Shohei;Kuraishi, Takashi

COMPUTERS & FLUIDS141p.124 - 1342016年-2016年

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ISSN:0045-7930

Computational analysis of wind-turbine blade rain erosion

Castorrini, Alessio;Corsini, Alessandro;Rispoli, Franco;Venturini, Paolo;Takizawa, Kenji;Tezduyar, Tayfun E.

COMPUTERS & FLUIDS141p.175 - 1832016年-2016年

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ISSN:0045-7930

Ram-air parachute structural and fluid mechanics computations with the Space-Time Isogeometric Analysis (ST-IGA)

Takizawa, Kenji;Tezduyar, Tayfun E.;Terahara, Takuya

COMPUTERS & FLUIDS141p.191 - 2002016年-2016年

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ISSN:0045-7930

Finite elements in flow problems 2015, Taiwan

Lin, Chao-An;Bazilevs, Yuri;Brummelen, E. Harald;Chen, Ching-Yao;Takizawa, Kenji

COMPUTERS & FLUIDS142p.1 - 22017年-2017年

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ISSN:0045-7930

Computational analysis of wind-turbine blade rain erosion

Castorrini, Alessio;Corsini, Alessandro;Rispoli, Franco;Venturini, Paolo;Takizawa, Kenji;Tezduyar, Tayfun E.

COMPUTERS & FLUIDS141p.175 - 1832016年-2016年

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ISSN:0045-7930

Turbocharger flow computations with the Space-Time Isogeometric Analysis (ST-IGA)

Takizawa, Kenji;Tezduyar, Tayfun E.;Otoguro, Yuto;Terahara, Takuya;Kuraishi, Takashi;Hattori, Hitoshi

COMPUTERS & FLUIDS142p.15 - 202017年-2017年

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ISSN:0045-7930

Computational analysis of flow-driven string dynamics in turbomachinery

Takizawa, Kenji;Tezduyar, Tayfun E.;Hattori, Hitoshi

COMPUTERS & FLUIDS142p.109 - 1172017年-2017年

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ISSN:0045-7930

Special methods for aerodynamic-moment calculations from parachute FSI modeling

Takizawa, Kenji; Tezduyar, Tayfun E.; Boswell, Cody; Tsutsui, Yuki; Montel, Kenneth

Computational Mechanics55(6)p.1059 - 10692015年10月-2015年10月 

DOIScopus

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ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg.The space–time fluid–structure interaction (STFSI) methods for 3D parachute modeling are now at a level where they can bring reliable, practical analysis to some of the most complex parachute systems, such as spacecraft parachutes. The methods include the Deforming-Spatial-Domain/Stabilized ST method as the core computational technology, and a good number of special FSI methods targeting parachutes. Evaluating the stability characteristics of a parachute based on how the aerodynamic moment varies as a function of the angle of attack is one of the practical analyses that reliable parachute FSI modeling can deliver. We describe the special FSI methods we developed for this specific purpose and present the aerodynamic-moment data obtained from FSI modeling of NASA Orion spacecraft parachutes and Japan Aerospace Exploration Agency (JAXA) subscale parachutes.

Computational analysis of flow-driven string dynamics in turbomachinery

Takizawa, Kenji;Tezduyar, Tayfun E.;Hattori, Hitoshi

COMPUTERS & FLUIDS142p.109 - 1172017年-2017年

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ISSN:0045-7930

Computational thermo-fluid analysis of a disk brake

Takizawa, Kenji; Tezduyar, Tayfun E.; Kuraishi, Takashi; Tabata, Shinichiro; Takagi, Hirokazu

Computational Mechanics57(6)p.965 - 9772016年06月-2016年06月 

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ISSN:01787675

概要:© 2016, Springer-Verlag Berlin Heidelberg.We present computational thermo-fluid analysis of a disk brake, including thermo-fluid analysis of the flow around the brake and heat conduction analysis of the disk. The computational challenges include proper representation of the small-scale thermo-fluid behavior, high-resolution representation of the thermo-fluid boundary layers near the spinning solid surfaces, and bringing the heat transfer coefficient (HTC) calculated in the thermo-fluid analysis of the flow to the heat conduction analysis of the spinning disk. The disk brake model used in the analysis closely represents the actual configuration, and this adds to the computational challenges. The components of the method we have developed for computational analysis of the class of problems with these types of challenges include the Space–Time Variational Multiscale method for coupled incompressible flow and thermal transport, ST Slip Interface method for high-resolution representation of the thermo-fluid boundary layers near spinning solid surfaces, and a set of projection methods for different parts of the disk to bring the HTC calculated in the thermo-fluid analysis. With the HTC coming from the thermo-fluid analysis of the flow around the brake, we do the heat conduction analysis of the disk, from the start of the breaking until the disk spinning stops, demonstrating how the method developed works in computational analysis of this complex and challenging problem.

Computation of free-surface flows and fluid-object interactions with the CIP method based on adaptive meshless soroban grids

Takizawa, Kenji;Yabe, Takashi;Tsugawa, Yumiko;Tezduyar, Tayfun E.;Mizoe, Hiroki

COMPUTATIONAL MECHANICS40(1)p.167 - 1832007年-2007年

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ISSN:0178-7675

Computation of fluid-solid and fluid-fluid interfaces with the CIP method based on adaptive Soroban grids - An overview

Yabe, Takashi;Takizawa, Kenji;Tezduyar, Tayfun E.;Im, Hyo-Nam

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS54(6-8)p.841 - 8532007年-2007年

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ISSN:0271-2091

Ship hydrodynamics computations with the CIP method based on adaptive Soroban grids

Takizawa, Kenji;Tanizawa, Katsuji;Yabe, Takashi;Tezduyar, Tayfun E.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS54(6-8)p.1011 - 10192007年-2007年

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ISSN:0271-2091

Conservative form of interpolated differential operator scheme for compressible and incompressible fluid dynamics

Imai, Yohsuke;Aoki, Takayuki;Takizawa, Kenji

JOURNAL OF COMPUTATIONAL PHYSICS227(4)p.2263 - 22852008年-2008年

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ISSN:0021-9991

Space-time finite element computation of arterial fluid-structure interactions with patient-specific data

Takizawa, Kenji;Christopher, Jason;Tezduyar, Tayfun E.;Sathe, Sunil

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING26(1)p.101 - 1162010年-2010年

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ISSN:2040-7939

Multiscale sequentially-coupled arterial FSI technique

Tezduyar, Tayfun E.;Takizawa, Kenji;Moorman, Creighton;Wright, Samuel;Christopher, Jason

COMPUTATIONAL MECHANICS46(1)p.17 - 292010年-2010年

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ISSN:0178-7675

Wall shear stress calculations in space-time finite element computation of arterial fluid-structure interactions

Takizawa, Kenji;Moorman, Creighton;Wright, Samuel;Christopher, Jason;Tezduyar, Tayfun E.

COMPUTATIONAL MECHANICS46(1)p.31 - 412010年-2010年

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ISSN:0178-7675

Solution of linear systems in arterial fluid mechanics computations with boundary layer mesh refinement

Manguoglu, Murat;Takizawa, Kenji;Sameh, Ahmed H.;Tezduyar, Tayfun E.

COMPUTATIONAL MECHANICS46(1)p.83 - 892010年-2010年

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ISSN:0178-7675

Space-time finite element computation of complex fluid-structure interactions

Tezduyar, Tayfun E.;Takizawa, Kenji;Moorman, Creighton;Wright, Samuel;Christopher, Jason

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS64(10-12)p.1201 - 12182010年-2010年

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ISSN:0271-2091

Nested and parallel sparse algorithms for arterial fluid mechanics computations with boundary layer mesh refinement

Manguoglu, Murat;Takizawa, Kenji;Sameh, Ahmed H.;Tezduyar, Tayfun E.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS65(1-3)p.135 - 1492011年-2011年

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ISSN:0271-2091

Fluid-structure interaction modeling and performance analysis of the Orion spacecraft parachutes

Takizawa, Kenji;Moorman, Creighton;Wright, Samuel;Spielman, Timothy;Tezduyar, Tayfun E.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS65(1-3)p.271 - 2852011年-2011年

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ISSN:0271-2091

Fluid-structure interaction modeling of parachute clusters

Takizawa, Kenji;Wright, Samuel;Moorman, Creighton;Tezduyar, Tayfun E.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS65(1-3)p.286 - 3072011年-2011年

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ISSN:0271-2091

Patient-specific arterial fluid-structure interaction modeling of cerebral aneurysms

Takizawa, Kenji;Moorman, Creighton;Wright, Samuel;Purdue, John;McPhail, Travis;Chen, Peng R.;Warren, Joe;Tezduyar, Tayfun E.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS65(1-3)p.308 - 3232011年-2011年

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ISSN:0271-2091

New directions and challenging computations in fluid dynamics modeling with stabilized and multiscale methods

Bazilevs, Yuri;Takizawa, Kenji;Tezduyar, Tayfun E.

MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES25(12)p.2217 - 22262015年-2015年

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ISSN:0218-2025

Multiscale space-time methods for thermo-fluid analysis of a ground vehicle and its tires

Takizawa, Kenji;Tezduyar, Tayfun E.;Kuraishi, Takashi

MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES25(12)p.2227 - 22552015年-2015年

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ISSN:0218-2025

Space-time VMS method for flow computations with slip interfaces (ST-SI)

Takizawa, Kenji;Tezduyar, Tayfun E.;Mochizuki, Hiroki;Hattori, Hitoshi;Mei, Sen;Pan, Linqi;Montel, Kenneth

MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES25(12)p.2377 - 24062015年-2015年

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ISSN:0218-2025

Space–time computational analysis of MAV flapping-wing aerodynamics with wing clapping

Takizawa, Kenji; Tezduyar, Tayfun E.; Buscher, Austin

Computational Mechanics55(6)p.1131 - 11412015年06月-2015年06月 

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ISSN:01787675

概要:© 2015, Springer-Verlag Berlin Heidelberg. Computational analysis of flapping-wing aerodynamics with wing clapping was one of the classes of computations targeted in introducing the space–time (ST) interface-tracking method with topology change (ST-TC). The ST-TC method is a new version of the deforming-spatial-domain/stabilized ST (DSD/SST) method, enhanced with a master–slave system that maintains the connectivity of the “parent” fluid mechanics mesh when there is contact between the moving interfaces. With that enhancement and because of its ST nature, the ST-TC method can deal with an actual contact between solid surfaces in flow problems with moving interfaces. It accomplishes that while still possessing the desirable features of interface-tracking (moving-mesh) methods, such as better resolution of the boundary layers. Earlier versions of the DSD/SST method, with effective mesh update, were already able to handle moving-interface problems when the solid surfaces are in near contact or create near TC. Flapping-wing aerodynamics of an actual locust, with the forewings and hindwings crossing each other very close and creating near TC, is an example of successfully computed problems. Flapping-wing aerodynamics of a micro aerial vehicle (MAV) with the wings of an actual locust is another example. Here we show how the ST-TC method enables 3D computational analysis of flapping-wing aerodynamics of an MAV with wing clapping. In the analysis, the wings are brought into an actual contact when they clap. We present results for a model dragonfly MAV.

Fluid–structure interaction

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Mechanics55(6)p.1057 - 10582015年05月-2015年05月 

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ISSN:01787675

FSI modeling of the Orion spacecraft drogue parachutes

Takizawa, Kenji; Tezduyar, Tayfun E.; Kolesar, Ryan

Computational Mechanics55(6)p.1167 - 11792015年12月-2015年12月 

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ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg.The space–time fluid–structure interaction (STFSI) methods for parachute modeling are now capable of bringing reliable analysis to spacecraft parachutes, which pose formidable computational challenges. A number of special FSI methods targeting spacecraft parachutes complement the STFSI core computational technology in addressing these challenges. Until recently, these challenges were addressed for the Orion spacecraft main parachutes, which are the parachutes used for landing, and in the incompressible-flow regime, which is where the main parachutes operate. At higher altitudes the Orion spacecraft will rely on drogue parachutes. These parachutes have a ribbon construction, and in FSI modeling this creates geometric and flow complexities comparable to those encountered in FSI modeling of the main parachutes, which have a ringsail construction. Like the main parachutes, the drogue parachutes will be used in multiple stages—two reefed stages and a fully-open stage. A reefed stage is where a cable along the parachute skirt constrains the diameter to be less than the diameter in the subsequent stage. After a period of time during the descent at the reefed stage, the cable is cut and the parachute disreefs (i.e. expands) to the next stage. The reefed stages and disreefing involve computational challenges beyond those in FSI modeling of fully-open drogue parachutes. We present the special modeling techniques we devised to address the computational challenges and the results from the computations carried out. The flight envelope of the Orion drogue parachutes includes regions where the Mach number is high enough to require a compressible-flow solver. We present a preliminary fluid mechanics computation for such a case.

Multiscale space-time methods for thermo-fluid analysis of a ground vehicle and its tires

Takizawa, Kenji; Tezduyar, Tayfun E.; Kuraishi, Takashi

Mathematical Models and Methods in Applied Sciences25(12)p.2227 - 22552015年01月-2015年01月 

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ISSN:02182025

概要:© 2015 World Scientific Publishing Company. We present the core and special multiscale space-time (ST) methods we developed for thermo-fluid analysis of a ground vehicle and its tires. We also present application of these methods to thermo-fluid analysis of a freight truck and its rear set of tires. The core multiscale ST method is the ST variational multiscale (ST-VMS) formulation of the Navier-Stokes equations of incompressible flows with thermal coupling, which is multiscale in the way the small-scale thermo-fluid behavior is represented in the computations. The special multiscale ST method is spatially multiscale, where the thermo-fluid computation over the global domain with a reasonable mesh refinement is followed by a higher-resolution computation over the local domain containing the rear set of tires, with the boundary and initial conditions coming from the data computed over the global domain. The large amount of time-history data from the global computation is stored using the ST computation technique with continuous representation in time (ST-C), which serves as a data compression technique in this context. In our thermo-fluid analysis, we use a road-surface temperature higher than the free-stream temperature, and a tire-surface temperature that is even higher. We also include in the analysis the heat from the engine and exhaust system, with a reasonably realistic representation of the rate by which that heat transfer takes place as well as the surface geometry of the engine and exhaust system over which the heat transfer occurs. We take into account the heave motion of the truck body. We demonstrate how the spatially multiscale ST method, with higher-refinement mesh in the local domain, substantially increases the accuracy of the computed heat transfer rates from the tires.

New directions and challenging computations in fluid dynamics modeling with stabilized and multiscale methods

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences25(12)p.2217 - 22262015年01月-2015年01月 

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ISSN:02182025

概要:© 2015 World Scientific Publishing Company. In this paper, we provide a brief overview of the development of stabilized and multiscale methods in fluid dynamics. We mainly focus on recent developments and new directions in the variational multiscale (VMS) methods. We also discuss applications of the VMS techniques to fluid dynamics problems involving computational challenges associated with high-Reynolds-number flows, wall-bounded turbulent flows, flows with moving domains including subdomains in relative motion, and free-surface flows.

Space-time VMS method for flow computations with slip interfaces (ST-SI)

Takizawa, Kenji; Tezduyar, Tayfun E.; Mochizuki, Hiroki; Hattori, Hitoshi; Mei, Sen; Pan, Linqi; Montel, Kenneth

Mathematical Models and Methods in Applied Sciences25(12)p.2377 - 24062015年01月-2015年01月 

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ISSN:02182025

概要:© 2015 World Scientific Publishing Company. We present the space-time variational multiscale (ST-VMS) method for flow computations with slip interfaces (ST-SI). The method is intended for fluid-structure interaction (FSI) analysis where one or more of the subdomains contain spinning structures, such as the rotor of a wind turbine, and the subdomains are covered by meshes that do not match at the interface and have slip between them. The mesh covering a subdomain with the spinning structure spins with it, thus maintaining the high-resolution representation of the boundary layers near the structure. The starting point in the development of the method is the version of the arbitrary Lagrangian-Eulerian VMS (ALE-VMS) method designed for computations with "sliding interfaces". Interface terms similar to those in the ALE-VMS version are added to the ST-VMS formulation to account for the compatibility conditions for the velocity and stress. In addition to having a high-resolution representation of the boundary layers, because the ST framework allows NURBS functions in temporal representation of the structure motion, we have exact representation of the circular paths associated with the spinning. The ST-SI method includes versions for cases where the SI is between fluid and solid domains with weakly-imposed Dirichlet conditions for the fluid and for cases where the SI is between a thin porous structure and the fluid on its two sides. Test computations with 2D and 3D models of a vertical-axis wind turbine show the effectiveness of the ST-SI method.

Turbocharger flow computations with the Space–Time Isogeometric Analysis (ST-IGA)

Takizawa, Kenji; Tezduyar, Tayfun E.; Otoguro, Yuto; Terahara, Takuya; Kuraishi, Takashi; Hattori, Hitoshi

Computers and Fluids142p.15 - 202017年01月-2017年01月 

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ISSN:00457930

概要:© 2016We focus on turbocharger computational flow analysis with a method that possesses higher accuracy in spatial and temporal representations. In the method we have developed for this purpose, we use a combination of (i) the Space–Time Variational Multiscale (ST-VMS) method, which is a stabilized formulation that also serves as a turbulence model, (ii) the ST Slip Interface (ST-SI) method, which maintains high-resolution representation of the boundary layers near spinning solid surfaces by allowing in a consistent fashion slip at the interface between the mesh covering a spinning surface and the mesh covering the rest of the domain, and (iii) the Isogeometric Analysis (IGA), where we use NURBS basis functions in space and time. The basis functions are spatially higher-order in all representations, and temporally higher-order in representation of the solid-surface and mesh motions. The ST nature of the method gives us higher-order accuracy in the flow solver, and when combined with temporally higher-order basis functions, a more accurate representation of the surface motion, and a mesh motion consistent with that. The spatially higher-order basis functions give us again higher-order accuracy in the flow solver, a more accurate, in some parts exact, representation of the surface geometry, and better representation in evaluating the second-order spatial derivatives. Using NURBS basis functions with a complex geometry is not trivial, however, once we generate the mesh, the computational efficiency is substantially increased. We focus on the turbine part of a turbocharger, but our method can also be applied to the compressor part and thus can be extended to the full turbocharger.

Computational analysis of flow-driven string dynamics in turbomachinery

Takizawa, Kenji; Tezduyar, Tayfun E.; Hattori, Hitoshi

Computers and Fluids142p.109 - 1172017年01月-2017年01月 

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ISSN:00457930

概要:© 2016 Elsevier LtdWe focus on computational analysis of flow-driven string dynamics. The objective is to understand how the strings carried by a fluid interact with the solid surfaces present and get stuck on or around those surfaces. Our target application is turbomachinery, such as understanding how strings get stuck on or around the blades of a fan. The components of the method we developed for this purpose are the Space–Time Variational Multiscale (ST-VMS) and ST Slip Interface (ST-SI) methods for the fluid dynamics, and a one-way-dependence model and the Isogeometric Analysis (IGA) for the string dynamics. The ST-VMS method is the core computational technology and it also has the features of a turbulence model. The ST-SI method allows in a consistent fashion slip at the interface between the mesh covering a spinning solid surface and the mesh covering the rest of the domain, and with this, we maintain high-resolution representation of the boundary layers near spinning solid surfaces such as fan blades. With the one-way-dependence model, we compute the influence of the flow on the string dynamics, while avoiding the formidable task of computing the influence of the string on the flow, which we expect to be small. The IGA for the string dynamics gives us not only a higher-order method and smoothness in the structure shape, but also smoothness in the fluid dynamics forces calculated on the string. To demonstrate how the method can be used in computational analysis of flow-driven string dynamics, we present the pilot computations we carried out, for a duct with cylindrical obstacles and for a ventilating fan.

Ram-air parachute structural and fluid mechanics computations with the Space–Time Isogeometric Analysis (ST-IGA)

Takizawa, Kenji; Tezduyar, Tayfun E.; Terahara, Takuya

Computers and Fluids141p.191 - 2002016年12月-2016年12月 

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詳細

ISSN:00457930

概要:© 2016 Elsevier LtdWe present a method for structural and fluid mechanics computations of ram-air parachutes. A ram-air parachute is a parafoil inflated by the airflow through the inlets at the leading edge. It has better control and gliding capability than round parachutes. Reliable analysis of ram-air parachutes requires accurate representation of the parafoil geometry, fabric porosity and the complex, multiscale flow behavior involved in this class of problems. The key components of the method are (i) the Space–Time Variational Multiscale (ST-VMS) method, (ii) the version of the ST Slip Interface (ST-SI) method where the SI is between a thin porous structure and the fluid on its two sides, (iii) the ST Isogeometric Analysis (ST-IGA), and (iv) special-purpose NURBS mesh generation techniques for the parachute structure and the flow field inside and outside the parafoil. The ST-VMS method is a stabilized formulation that also serves as a turbulence model and can deal effectively with the complex, multiscale flow behavior. With the ST-SI version for porosity modeling, we deal with the fabric porosity in a fashion consistent with how we deal with the standard SIs and how we enforce the Dirichlet boundary conditions weakly. The ST-IGA, with NURBS basis functions in space, gives us, with relatively few number of unknowns, accurate representation of the parafoil geometry and increased accuracy in the flow solution. The special-purpose mesh generation techniques enable NURBS representation of the structure and fluid domains with significant geometric complexity. The test computations we present are for building a starting parachute shape and a starting flow field associated with that parachute shape, which are the first two key steps in fluid–structure interaction analysis. The computations demonstrate the effectiveness of the method in this class of problems.

Preface

Bazilevs, Yuri; Takizawa, Kenji

Modeling and Simulation in Science, Engineering and Technology2016年01月-2016年01月 

Scopus

詳細

ISSN:21643679

SUPG/PSPG computational analysis of rain erosion in wind-turbine blades

Castorrini, Alessio; Corsini, Alessandro; Rispoli, Franco; Venturini, Paolo; Takizawa, Kenji; Tezduyar, Tayfun E.

Modeling and Simulation in Science, Engineering and Technologyp.77 - 962016年01月-2016年01月 

DOIScopus

詳細

ISSN:21643679

概要:© Springer International Publishing Switzerland 2016.Wind-turbine blades exposed to rain can be damaged by erosion if not protected. Although this damage does not typically influence the structural response of the blades,it could heavily degrade the aerodynamic performance,and therefore the power production. We present a method for computational analysis of rain erosion in wind-turbine blades. The method is based on a stabilized finite element fluid mechanics formulation and a finite element particle-cloud tracking method. Accurate representation of the flow would be essential in reliable computational turbomachinery analysis and design. The turbulent-flow nature of the problem is dealt with a RANS model and SUPG/PSPG stabilization,the particle-cloud trajectories are calculated based on the flow field and closure models for the turbulence-particle interaction,and one-way dependence is assumed between the flow field and particle dynamics. The erosion patterns are then computed based on the particle-cloud data.

New directions in space-time computational methods

Takizawa, Kenji; Tezduyar, Tayfun E.

Modeling and Simulation in Science, Engineering and Technologyp.159 - 1782016年01月-2016年01月 

DOIScopus

詳細

ISSN:21643679

概要:© Springer International Publishing Switzerland 2016.This is an overview of some of the new directions we have taken the space-time (ST) computational methods since 2010 in bringing solution and analysis to different classes of challenging engineering problems. The new directions include the variational multiscale (VMS) version of the Deforming-Spatial-Domain/Stabilized ST method,using NURBS basis functions in temporal representation of the unknown variables and motion of the solid surfaces and fluid mechanics meshes,ST techniques with continuous representation in time,ST interface-tracking with topology change,and the ST-VMS method for flow computations with slip interfaces. We describe these new directions and present a few examples.

Finite elements in flow problems 2015

Lin, Chao An; Bazilevs, Yuri; van Brummelen, Harald; Takizawa, Kenji; Wu, Jong Shinn

Computers and Mathematics with Applications72(8)p.1957 - 19582016年10月-2016年10月 

DOIScopus

詳細

ISSN:08981221

Aorta modeling with the element-based zero-stress state and isogeometric discretization

Takizawa, Kenji; Tezduyar, Tayfun E.; Sasaki, Takafumi

Computational Mechanics59(2)p.265 - 2802017年02月-2017年02月 

DOIScopus

詳細

ISSN:01787675

概要:© 2016, Springer-Verlag Berlin Heidelberg. Patient-specific arterial fluid–structure interaction computations, including aorta computations, require an estimation of the zero-stress state (ZSS), because the image-based arterial geometries do not come from a ZSS. We have earlier introduced a method for estimation of the element-based ZSS (EBZSS) in the context of finite element discretization of the arterial wall. The method has three main components. 1. An iterative method, which starts with a calculated initial guess, is used for computing the EBZSS such that when a given pressure load is applied, the image-based target shape is matched. 2. A method for straight-tube segments is used for computing the EBZSS so that we match the given diameter and longitudinal stretch in the target configuration and the “opening angle.” 3. An element-based mapping between the artery and straight-tube is extracted from the mapping between the artery and straight-tube segments. This provides the mapping from the arterial configuration to the straight-tube configuration, and from the estimated EBZSS of the straight-tube configuration back to the arterial configuration, to be used as the initial guess for the iterative method that matches the image-based target shape. Here we present the version of the EBZSS estimation method with isogeometric wall discretization. With isogeometric discretization, we can obtain the element-based mapping directly, instead of extracting it from the mapping between the artery and straight-tube segments. That is because all we need for the element-based mapping, including the curvatures, can be obtained within an element. With NURBS basis functions, we may be able to achieve a similar level of accuracy as with the linear basis functions, but using larger-size and much fewer elements. Higher-order NURBS basis functions allow representation of more complex shapes within an element. To show how the new EBZSS estimation method performs, we first present 2D test computations with straight-tube configurations. Then we show how the method can be used in a 3D computation where the target geometry is coming from medical image of a human aorta.

Computational Fluid–Structure Interaction and Flow Simulation

Bazilevs, Yuri; Takizawa, Kenji

Computers and Fluids1412016年12月-2016年12月 

DOIScopus

詳細

ISSN:00457930

Space–Time method for flow computations with slip interfaces and topology changes (ST-SI-TC)

Takizawa, Kenji; Tezduyar, Tayfun E.; Asada, Shohei; Kuraishi, Takashi

Computers and Fluids141p.124 - 1342016年12月-2016年12月 

DOIScopus

詳細

ISSN:00457930

概要:© 2016 Elsevier LtdThe Space–Time Variational Multiscale (ST-VMS) method was introduced to function as a moving-mesh method. It is the VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method. It has reasonably good turbulence modeling features and serves as a core computational method. The ST Slip Interface (ST-SI) method was introduced to addresses the challenge involved in high-resolution representation of the boundary layers near spinning solid surfaces. The mesh covering a spinning solid surface spins with it and thus maintains the high-resolution representation near it. The ST-TC method was introduced for moving-mesh computation of flow problems with topology changes, such as contact between solid surfaces. It deals with the TC while maintaining high-resolution boundary layer representation near solid surfaces. The “ST-SI-TC” method we introduce here integrates the ST-SI and ST-TC methods in the ST-VMS framework. It enables accurate flow analysis when we have a spinning solid surface that is in contact with a solid surface. We present two test computations with the ST-SI-TC method, and they are both with models of flow around a rotating tire with road contact and prescribed deformation, one with a 2D model, and one with a 3D model.

Computational analysis of wind-turbine blade rain erosion

Castorrini, Alessio; Corsini, Alessandro; Rispoli, Franco; Venturini, Paolo; Takizawa, Kenji; Tezduyar, Tayfun E.

Computers and Fluids141p.175 - 1832016年12月-2016年12月 

DOIScopus

詳細

ISSN:00457930

概要:© 2016 Elsevier LtdWind-turbine blade rain erosion damage could be significant if the blades are not protected. This damage would not typically influence the structural integrity of the blades, but it could degrade the aerodynamic performance and therefore the power production. We present computational analysis of rain erosion in wind-turbine blades. The main components of the method used in the analysis are the Streamline-Upwind/Petrov–Galerkin (SUPG) and Pressure-Stabilizing/Petrov–Galerkin (PSPG) stabilizations, a finite element particle-cloud tracking method, and an erosion model. The turbulent-flow nature of the analysis is handled with a RANS model and SUPG/PSPG stabilization, the particle-cloud trajectories are calculated based on the computed flow field and closure models defined for the turbulent dispersion of particles, and one-way dependence is assumed between the flow and particle dynamics. The erosion patterns are then computed based on the particle-cloud data. The patterns are consistent with those observed in the actual wind turbines.

Finite elements in flow problems 2015, Taiwan

Lin, Chao An; Bazilevs, Yuri; Brummelen, E. Harald; Chen, Ching Yao; Takizawa, Kenji

Computers and Fluids142p.1 - 22017年01月-2017年01月 

DOIScopus

詳細

ISSN:00457930

Heart valve flow computation with the integrated Space–Time VMS, Slip Interface, Topology Change and Isogeometric Discretization methods

Takizawa, Kenji; Tezduyar, Tayfun E.; Terahara, Takuya; Sasaki, Takafumi

Computers and Fluids158p.176 - 1882017年11月-2017年11月 

DOIScopus

詳細

ISSN:00457930

概要:© 2016 Elsevier Ltd Heart valve flow computation requires accurate representation of boundary layers near moving solid surfaces, including the valve leaflet surfaces, even when the leaflets come into contact. It also requires dealing with a high level of geometric complexity. We address these computational challenges with a Space–Time (ST) method developed by integrating three special ST methods in the framework of the ST Variational Multiscale (ST-VMS) method. The special methods are the ST Slip Interface (ST-SI) and ST Topology Change (ST-TC) methods and ST Isogeometric Analysis (ST-IGA). The computations are for a realistic aortic-valve model with prescribed valve leaflet motion and actual contact between the leaflets. The ST-VMS method functions as a moving-mesh method, which maintains high-resolution boundary layer representation near the solid surfaces, including leaflet surfaces. The ST-TC method was introduced for moving-mesh computation of flow problems with TC, such as contact between the leaflets of a heart valve. It deals with the contact while maintaining high-resolution representation near the leaflet surfaces. The ST-SI method was originally introduced to have high-resolution representation of the boundary layers near spinning solid surfaces. The mesh covering a spinning solid surface spins with it, and the SI between the spinning mesh and the rest of the mesh accurately connects the two sides. In the context of heart valves, the SI connects the sectors of meshes containing the leaflets, enabling a more effective mesh moving. In that context, integration of the ST-SI and ST-TC methods enables high-resolution representation even when the contact is between leaflets that are covered by meshes with SI. It also enables dealing with contact location change or contact and sliding on the SI. By integrating the ST-IGA with the ST-SI and ST-TC methods, in addition to having a more accurate representation of the surfaces and increased accuracy in the flow solution, the element density in the narrow spaces near the contact areas is kept at a reasonable level. Furthermore, because the flow representation in the contact area has a wider support in IGA, the flow computation method becomes more robust. The computatio ns we present for an aortic-valve model with two different modes of prescribed leaflet motion show the effectiveness of the ST-SI-TC-IGA method.

Porosity models and computational methods for compressible-flow aerodynamics of parachutes with geometric porosity

Takizawa, Kenji; Tezduyar, Tayfun E.; Kanai, Taro

Mathematical Models and Methods in Applied Sciences27(4)p.771 - 8062017年04月-2017年04月 

DOIScopus

詳細

ISSN:02182025

概要:© 2017 World Scientific Publishing Company. Spacecraft-parachute designs quite often include "geometric porosity" created by the hundreds of gaps and slits that the flow goes through. Computational fluid-structure interaction (FSI) analysis of these parachutes with resolved geometric porosity would be exceedingly challenging, and therefore accurate modeling of the geometric porosity is essential for reliable FSI analysis. The space-time FSI (STFSI) method with the homogenized modeling of geometric porosity has proven to be reliable in computational analysis and design studies of Orion spacecraft parachutes in the incompressible-flow regime. Here we introduce porosity models and ST computational methods for compressible-flow aerodynamics of parachutes with geometric porosity. The main components of the ST computational framework we use are the compressible-flow ST SUPG method, which was introduced earlier, and the compressible-flow ST Slip Interface method, which we introduce here. The computations we present for a drogue parachute show the effectiveness of the porosity models and ST computational methods.

Space–time VMS computational flow analysis with isogeometric discretization and a general-purpose NURBS mesh generation method

Otoguro, Yuto; Takizawa, Kenji; Tezduyar, Tayfun E.

Computers and Fluids158p.189 - 2002017年11月-2017年11月 

DOIScopus

詳細

ISSN:00457930

概要:© 2017 Elsevier Ltd The Space–Time Computational Analysis (STCA) with key components that include the ST Variational Multiscale (ST-VMS) method and ST Isogeometric Analysis (ST-IGA) is being increasingly used in fluid mechanics computations with complex geometries. In such computations, the ST-VMS serves as the core method, complemented by the ST-IG A, and sometimes by additional key components, such as the ST Slip Interface (ST-SI) method. To make the ST-IGA use, and in a wider context the IGA use, even more practical in fluid mechanics computations, NURBS volume mesh generation needs to be easier and as automated as possible. To that end, we present a general-purpose NURBS mesh generation method. The method is based on multi-block structured mesh generation with existing techniques, projection of that mesh to a NURBS mesh made of patches that correspond to the blocks, and recovery of the original model surfaces to the extent they are suitable for accurate and robust fluid mechanics computations. It is expected to retain the refinement distribution and element quality of the multi-block structured mesh that we start with. The flexibility of discretization with the general-purpose mesh generation is supplemented with the ST-SI method, which allows, without loss of accuracy, C −1 continuity between NURBS patches and thus removes the matching requirement between the patches. We present a test computation for a turbocharger turbine and exhaust manifold, which demonstrates that the general-purpose mesh generation method proposed makes the IGA use in fluid mechanics computations even more practical.

Heart valve flow computation with the space-time slip interface topology change (ST-SI-TC) method and isogeometric analysis (IGA)

Takizawa, Kenji; Tezduyar, Tayfun E.; Terahara, Takuya; Sasaki, Takafumi

Lecture Notes in Applied and Computational Mechanics84p.77 - 992018年01月-2018年01月 

DOIScopus

詳細

ISSN:16137736

概要:© Springer International Publishing AG 2018. We present a heart valve flow computation with the Space-Time Slip Interface Topology Change (ST-SI-TC) method and Isogeometric Analysis (IGA). The computation is for a realistic heart valve model with actual contact between the valve leaflets. The ST-SI-TC method integrates the ST-SI and ST-TC methods in the framework of the ST Variational Multiscale (ST-VMS) method. The STVMS method functions as a moving-mesh method, which maintains high-resolution boundary layer representation near the solid surfaces. The ST-TC method was introduced for moving-mesh computation of flow problems with TC, such as contact between the leaflets of a heart valve. It deals with the contact while maintaining highresolution representation near the leaflet surfaces. The ST-SI method was originally introduced to addresses the challenge involved in high-resolution representation of the boundary layers near spinning solid surfaces. The mesh covering a spinning solid surface spins with it, and the SI between that mesh and the rest of the mesh accurately connects the two sides. This maintains the high-resolution representation near solid surfaces. In the context of heart valves, the SI connects the sectors of meshes containing the leaflets, enabling a more effective mesh moving. In that context, the ST-SI-TC method enables high-resolution representation even when the contact is between leaflets that are covered by meshes with SI. It also enables dealing with contact location change or contact and sliding on the SI. With IGA, in addition to having a more accurate representation of the surfaces and increased accuracy in the flow solution, the element density in the narrow spaces near the contact areas is kept at a reasonable level. Furthermore, because the flow representation in the contact area has a wider support in IGA, the flow computation method becomes more robust. The computation we present for an aortic-valve model shows the effectiveness of the ST-SI-TC-IGA method.

Estimation of element-based zero-stress state in arterial FSI computations with isogeometric wall discretization

Takizawa, Kenji; Tezduyar, Tayfun E.; Sasaki, Takafumi

Lecture Notes in Applied and Computational Mechanics84p.101 - 1222018年01月-2018年01月 

DOIScopus

詳細

ISSN:16137736

概要:© Springer International Publishing AG 2018. In patient-specific arterial fluid-structure interaction computations the image-based arterial geometry does not come from a zero-stress state (ZSS), requiring an estimation of the ZSS. A method for estimation of element-based ZSS (EBZSS) was introduced earlier in the context of finite element wall discretization. The method has three main components. 1. An iterative method, which starts with a calculated initial guess, is used for computing the EBZSS such that when a given pressure load is applied, the image-based target shape is matched. 2. A method for straight-tube segments is used for computing the EBZSS so that we match the given diameter and longitudinal stretch in the target configuration and the “opening angle.” 3. An element-based mapping between the artery and straight-tube is extracted from the mapping between the artery and straight-tube segments. This provides the mapping from the arterial configuration to the straight-tube configuration, and from the estimated EBZSS of the straight-tube configuration back to the arterial configuration, to be used as the initial guess for the iterative method that matches the image-based target shape. Here we introduce the version of the EBZSS estimation method with isogeometric wall discretization. With NURBS basis functions, we may be able to use larger elements, consequently less number of elements, compared to linear basis functions. Higher-order NURBS basis functions allow representation of more complex shapes within an element. To show how the new EBZSS estimation method performs, we present 2D test computations with straight-tube configurations.

Special issue on computational fluid mechanics and fluid-structure interaction: Preface

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Mechanics48(3)2011年09月-2011年09月 

DOIScopus

詳細

ISSN:01787675

A parallel sparse algorithm targeting arterial fluid mechanics computations

Manguoglu, Murat; Takizawa, Kenji; Sameh, Ahmed H.; Tezduyar, Tayfun E.

Computational Mechanics48(3)p.377 - 3842011年09月-2011年09月 

DOIScopus

詳細

ISSN:01787675

概要:Iterative solution of large sparse nonsymmetric linear equation systems is one of the numerical challenges in arterial fluid-structure interaction computations. This is because the fluid mechanics parts of the fluid + structure block of the equation system that needs to be solved at every nonlinear iteration of each time step corresponds to incompressible flow, the computational domains include slender parts, and accurate wall shear stress calculations require boundary layer mesh refinement near the arterial walls. We propose a hybrid parallel sparse algorithm, domain-decomposing parallel solver (DDPS), to address this challenge. As the test case, we use a fluid mechanics equation system generated by starting with an arterial shape and flow field coming from an FSI computation and performing two time steps of fluid mechanics computation with a prescribed arterial shape change, also coming from the FSI computation. We show how the DDPS algorithm performs in solving the equation system and demonstrate the scalability of the algorithm. © 2011 Springer-Verlag.

Stabilized space-time computation of wind-turbine rotor aerodynamics

Takizawa, Kenji; Henicke, Bradley; Tezduyar, Tayfun E.; Hsu, Ming Chen; Bazilevs, Yuri

Computational Mechanics48(3)p.333 - 3442011年09月-2011年09月 

DOIScopus

詳細

ISSN:01787675

概要:We show how we use the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation for accurate 3D computation of the aerodynamics of a wind-turbine rotor. As the test case, we use the NREL 5MW offshore baseline wind-turbine rotor. This class of computational problems are rather challenging, because they involve large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. We compute the problem with both the original version of the DSD/SST formulation and a recently introduced version with an advanced turbulence model. The DSD/SST formulation with the advanced turbulence model is a space-time version of the residual-based variational multiscale method. We compare our results to those reported recently, which were obtained with the residual-based variational multiscale Arbitrary Lagrangian-Eulerian method using NURBS for spatial discretization and which we take as the reference solution. While the original DSD/SST formulation yields torque values not far from the reference solution, the DSD/SST formulation with the variational multiscale turbulence model yields torque values very close to the reference solution. © 2011 Springer-Verlag.

Space-time FSI modeling and dynamical analysis of spacecraft parachutes and parachute clusters

Takizawa, Kenji; Spielman, Timothy; Tezduyar, Tayfun E.

Computational Mechanics48(3)p.345 - 3642011年09月-2011年09月 

DOIScopus

詳細

ISSN:01787675

概要:Computer modeling of spacecraft parachutes, which are quite often used in clusters of two or three large parachutes, involves fluid-structure interaction (FSI) between the parachute canopy and the air, geometric complexities created by the construction of the parachute from "rings" and "sails" with hundreds of gaps and slits, and the contact between the parachutes. The Team for Advanced Flow Simulation and Modeling (T*AFSM) has successfully addressed the computational challenges related to the FSI and geometric complexities, and recently started addressing the challenges related to the contact between the parachutes of a cluster. The core numerical technology is the stabilized space-time FSI technique developed and improved over the years by the (T*AFSM) . The special technique used in dealing with the geometric complexities is the Homogenized Modeling of Geometric Porosity, which was also developed and improved in recent years by the (T*AFSM) . In this paper we describe the technique developed by the (T*AFSM) for modeling, in the context of an FSI problem, the contact between two structural surfaces. We show how we use this technique in dealing with the contact between parachutes. We present the results obtained with the FSI computation of parachute clusters, the related dynamical analysis, and a special decomposition technique for parachute descent speed to make that analysis more informative. We also present a special technique for extracting from a parachute FSI computation model parameters, such as added mass, that can be used in fast, approximate engineering analysis models for parachute dynamics. © 2011 Springer-Verlag.

Multiscale space-time fluid-structure interaction techniques

Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Mechanics48(3)p.247 - 2672011年09月-2011年09月 

DOIScopus

詳細

ISSN:01787675

概要:We present the multiscale space-time techniques we have developed for fluid-structure interaction (FSI) computations. Some of these techniques are multiscale in the way the time integration is performed (i.e. temporally multiscale), some are multiscale in the way the spatial discretization is done (i.e. spatially multiscale), and some are in the context of the sequentially-coupled FSI (SCFSI) techniques developed by the Team for Advanced Flow Simulation and Modeling T AFSM . In the multiscale SCFSI technique, the FSI computational effort is reduced at the stage we do not need it and the accuracy of the fluid mechanics (or structural mechanics) computation is increased at the stage we need accurate, detailed flow (or structure) computation. As ways of increasing the computational accuracy when or where needed, and beyond just increasing the mesh refinement or decreasing the time-step size, we propose switching to more accurate versions of the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation, using more polynomial power for the basis functions of the spatial discretization or time integration, and using an advanced turbulence model. Specifically, for more polynomial power in time integration, we propose to use NURBS, and as an advanced turbulence model to be used with the DSD/SST formulation, we introduce a space-time version of the residual-based variational multiscale method. We present a number of test computations showing the performance of the multiscale space-time techniques we are proposing. We also present a stability and accuracy analysis for the higher-accuracy versions of the DSD/SST formulation. © 2011 Springer-Verlag.

Space-time fluid-structure interaction modeling of patient-specific cerebral aneurysms

Tezduyar, Tayfun E.; Takizawa, Kenji; Brummer, Tyler; Chen, Peng R.

International Journal for Numerical Methods in Biomedical Engineering27(11)p.1665 - 17102011年11月-2011年11月 

DOIScopus

詳細

ISSN:20407939

概要:We provide an extensive overview of the core and special techniques developed earlier by the Team for Advanced Flow Simulation and Modeling (T{black star}AFSM) for space-time fluid-structure interaction (FSI) modeling of patient-specific cerebral aneurysms. The core FSI techniques are the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation and the stabilized space-time FSI (SSTFSI) technique. The special techniques include techniques for calculating an estimated zero-pressure (EZP) arterial geometry, a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, techniques for using variable arterial wall thickness, mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, a recipe for pre-FSI computations that improve the convergence of the FSI computations, the Sequentially-Coupled Arterial FSI (SCAFSI) technique and its multiscale versions, techniques for the projection of fluid-structure interface stresses, calculation of the wall shear stress (WSS) and calculation of the oscillatory shear index (OSI) and arterial-surface extraction and boundary condition techniques. We show how these techniques work with results from earlier computations. We also describe the arterial FSI techniques developed and implemented recently by the T{black star}AFSM and present a sample from a wide set of patient-specific cerebral-aneurysm models we computed recently. © 2011 John Wiley & Sons, Ltd.

Fluid-structure interaction modeling of ringsail parachute clusters

Takizawa, K.; Spielman, T.; Tezduyar, T. E.

AIP Conference Proceedings1376p.7 - 112011年11月-2011年11月 

DOIScopus

詳細

ISSN:0094243X

概要:The team for advanced flow simulation and modeling (TBlack starAFSM) has successfully addressed many of the computational challenges involved in fluid-structure interaction (FSI) modeling of ringsail parachutes, including the geometric complexities, and recently started addressing the challenges related to the contact between the parachutes of a cluster. This is being accomplished with the stabilized space-time FSI technique, which was developed by the TBlack starAFSM and serves as the core numerical technology, and the special techniques developed by the TBlack starAFSM. We present the results obtained with the FSI computation of parachute clusters and the related dynamical analysis. © 2011 American Institute of Physics.

Numerical-performance studies for the stabilized space-time computation of wind-turbine rotor aerodynamics

Takizawa, Kenji; Henicke, Bradley; Montes, Darren; Tezduyar, Tayfun E.; Hsu, Ming Chen; Bazilevs, Yuri

Computational Mechanics48(6)p.647 - 6572011年12月-2011年12月 

DOIScopus

詳細

ISSN:01787675

概要:We present our numerical-performance studies for 3D wind-turbine rotor aerodynamics computation with the deforming-spatial-domain/stabilized space-time (DSD/SST) formulation. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. As the test case, we use the NREL 5MW offshore baseline wind-turbine rotor. We compute the problem with both the original version of the DSD/SST formulation and the version with an advanced turbulence model. The DSD/SST formulation with the turbulence model is a recently-introduced space-time version of the residual-based variational multiscale method. We include in our comparison as reference solution the results obtained with the residual-based variational multiscale Arbitrary Lagrangian-Eulerian method using NURBS for spatial discretization. We test different levels of mesh refinement and different definitions for the stabilization parameter embedded in the "least squares on incompressibility constraint" stabilization. We compare the torque values obtained. © 2011 Springer-Verlag.

Space-time computational techniques for the aerodynamics of flapping wings

Takizawa, Kenji; Henicke, Bradley; Puntel, Anthony; Spielman, Timothy; Tezduyar, Tayfun E.

Journal of Applied Mechanics, Transactions ASME79(1)2012年01月-2012年01月 

DOIScopus

詳細

ISSN:00218936

概要:We present the special space-time computational techniques we have introduced recently for computation of flow problems with moving and deforming solid surfaces. The techniques have been designed in the context of the deforming-spatial-domain/stabilized space-time formulation, which was developed by the Team for Advanced Flow Simulation and Modeling for computation of flow problems with moving boundaries and interfaces. The special space-time techniques are based on using, in the space-time flow computations, non-uniform rational B-splines (NURBS) basis functions for the temporal representation of the motion and deformation of the solid surfaces and also for the motion and deformation of the volume meshes computed. This provides a better temporal representation of the solid surfaces and a more effective way of handling the volume-mesh motion. We apply these techniques to computation of the aerodynamics of flapping wings, specifically locust wings, where the prescribed motion and deformation of the wings are based on digital data extracted from the videos of the locust in a wind tunnel. We report results from the preliminary computations. © 2012 American Society of Mechanical Engineers.

A comparative study based on patient-specific fluid-structure interaction modeling of cerebral aneurysms

Takizawa, Kenji; Brummer, Tyler; Tezduyar, Tayfun E.; Chen, Peng R.

Journal of Applied Mechanics, Transactions ASME79(1)2012年01月-2012年01月 

DOIScopus

詳細

ISSN:00218936

概要:We present an extensive comparative study based on patient-specific fluid-structure interaction (FSI) modeling of cerebral aneurysms. We consider a total of ten cases, at three different locations, half of which ruptured. We use the stabilized space-time FSI technique developed by the Team for Advanced Flow Simulation and Modeling (T AFSM), together with a number of special techniques targeting arterial FSI modeling, which were also developed by the T AFSM. What we look at in our comparisons includes the wall shear stress, oscillatory shear index and the arterial-wall stress and stretch. We also investigate how simpler approaches to computer modeling of cerebral aneurysms perform compared to FSI modeling. © 2012 American Society of Mechanical Engineers.

Fluid-structure interaction modeling of spacecraft parachutes for simulation-based design

Takizawa, Kenji; Spielman, Timothy; Moorman, Creighton; Tezduyar, Tayfun E.

Journal of Applied Mechanics, Transactions ASME79(1)2012年01月-2012年01月 

DOIScopus

詳細

ISSN:00218936

概要:Even though computer modeling of spacecraft parachutes involves a number of numerical challenges, advanced techniques developed in recent years for fluid-structure interaction (FSI) modeling in general and for parachute FSI modeling specifically have made simulation-based design studies possible. In this paper we focus on such studies for a single main parachute to be used with the Orion spacecraft. Although these large parachutes are typically used in clusters of two or three parachutes, studies for a single parachute can still provide valuable information for performance analysis and design and can be rather extensive. The major challenges in computer modeling of a single spacecraft parachute are the FSI between the air and the parachute canopy and the geometric complexities created by the construction of the parachute from rings and sails with hundreds of gaps and slits. The Team for Advanced Flow Simulation and Modeling has successfully addressed the computational challenges related to the FSI and geometric complexities, and has also been devising special procedures as needed for specific design parameter studies. In this paper we present parametric studies based on the suspension line length, canopy loading, and the length of the overinflation control line. © 2012 American Society of Mechanical Engineers.

Special issue on computational fluid mechanics and fluid-structure interaction preface

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Journal of Applied Mechanics, Transactions ASME79(1)2012年01月-2012年01月 

DOIScopus

詳細

ISSN:00218936

Computational Methods for Parachute Fluid-Structure Interactions

Takizawa, Kenji; Tezduyar, Tayfun E.

Archives of Computational Methods in Engineering19(1)p.125 - 1692012年03月-2012年03月 

DOIScopus

詳細

ISSN:11343060

概要:The computational challenges posed by fluid-structure interaction (FSI) modeling of parachutes include the lightness of the parachute canopy compared to the air masses involved in the parachute dynamics, in the case of "ringsail" parachutes the geometric complexities created by the construction of the canopy from "rings" and "sails" with hundreds of ring "gaps" and sail "slits", and in the case of parachute clusters the contact between the parachutes. The Team for Advanced Flow Simulation and Modeling (T*AFSM) has successfully addressed these computational challenges with the Stabilized Space-Time FSI (SSTFSI) technique, which was developed and improved over the years by the T*AFSM and serves as the core numerical technology, and a number of special techniques developed in conjunction with the SSTFSI technique. The quasi-direct and direct coupling techniques developed by the T*AFSM, which are applicable to cases with incompatible fluid and structure meshes at the interface, yield more robust algorithms for FSI computations where the structure is light and therefore more sensitive to the variations in the fluid dynamics forces. The special technique used in dealing with the geometric complexities of the rings and sails is the Homogenized Modeling of Geometric Porosity, which was developed and improved in recent years by the T*AFSM. The Surface-Edge-Node Contact Tracking (SENCT) technique was introduced by the T*AFSM as a contact algorithm where the objective is to prevent the structural surfaces from coming closer than a minimum distance in an FSI computation. The recently-introduced conservative version of the SENCT technique is more robust and is now an essential technology in the parachute cluster computations carried out by the T*AFSM. We provide an overview of the core and special techniques developed by the T*AFSM, present single-parachute FSI computations carried out for design-parameter studies, and report FSI computation and dynamical analysis of two-parachute clusters. © 2012 CIMNE, Barcelona, Spain.

Multiscale space-time computation techniques

Takizawa, Kenji; Tezduyar, Tayfun E.

Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011p.611 - 6222011年12月-2011年12月 

Scopus

詳細

概要:A number of multiscale space-time techniques have been developed recently by the Team for Advanced Flow Simulation and Modeling (T*AFSM) for fluid-structure interaction computations. As part of that, we have introduced a space-time version of the residual-based variational multiscale method. It has been designed in the context of the Deforming-Spatial-Domain/Stabilized Space-Time formulation, which was developed earlier by the T*AFSM for computation of flow problems with moving boundaries and interfaces. We describe this multiscale space-time technique, and present results from test computations.

Space-time FSI modeling and dynamical analysis of ringsail parachute clusters

Takizawa, Kenji; Spielman, Timothy; Tezduyar, Tayfun E.

Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011p.43 - 542011年12月-2011年12月 

Scopus

詳細

概要:Computer modeling of ringsail parachute clusters involves fluid-structure interaction (FSI) between the parachute canopy and the air, geometric complexities created by the construction of the parachute from "rings" and "sails" with hundreds of gaps and slits, and the contact between the parachutes. The Team for Advanced Flow Simulation and Modeling (T*AFSM) has successfully addressed the computational challenges related to the FSI and geometric complexities, and recently started addressing the challenges related to the contact between the parachutes of a cluster. This is being accomplished with the Stabilized Space-Time FSI technique, which was developed and improved over the years by the T*AFSM and serves as the core numerical technology, and the special techniques developed by the T*AFSM to deal with the geometric complexities and the contact between parachutes. We present the results obtained with the FSI computation of parachute clusters and the related dynamical analysis.

Multiscale sequentially-coupled FSI computation in parachute modeling

Takizawa, Kenji; Wright, Samuel; Christopher, Jason; Tezduyar, Tayfun E.

Structural Membranes 2011 - 5th International Conference on Textile Composites and Inflatable Structuresp.385 - 3962011年12月-2011年12月 

Scopus

詳細

概要:We describe how the spatially multiscale Sequentially-Coupled Fluid-Structure Interaction (SCFSI) techniques we have developed, specifically the "SCFSI M2C", which is spatially multiscale for the structural mechanics part, can be used for increasing the accuracy of the membrane and cable structural mechanics solution in parachute FSI computations. The SCFSI M2C technique is used here in conjunction with the Stabilized Space-Time FSI (SSTFSI) technique, which was developed and improved over the years by the Team for Advanced Flow Simulation and Modeling (T *AFSM) and serves as the core numerical technology, and a number of special parachute FSI techniques developed by the T *AFSM in conjunction with the SSTFSI technique.

Space-time fsi modeling of ringsail parachute clusters

Takizawa, Kenji; Spielman, Timothy; Tezduyar, Tayfun E.

Structural Membranes 2011 - 5th International Conference on Textile Composites and Inflatable Structuresp.55 - 662011年12月-2011年12月 

Scopus

詳細

概要:The computational challenges posed by fluid-structure interaction (FSI) modeling of ringsail parachute clusters include the lightness of the membrane and cable structure of the canopy compared to the air masses involved in the parachute dynamics, geometric complexities created by the construction of the canopy from "rings" and "sails" with hundreds of ring gaps and sail slits, and the contact between the parachutes. The Team for Advanced Flow Simulation and Modeling (T *AFSM) has successfully addressed these computational challenges with the Stabilized Space-Time FSI technique (SSTFSI), which was developed and improved over the years by the T *AFSM and serves as the core numerical technology, and a number of special techniques developed in conjunction with the SSTFSI. We present the results obtained with the FSI computation of parachute clusters and the related dynamical analysis.

Space-Time and ALE-VMS Techniques for Patient-Specific Cardiovascular Fluid-Structure Interaction Modeling

Takizawa, Kenji; Bazilevs, Yuri; Tezduyar, Tayfun E.

Archives of Computational Methods in Engineering19(2)p.171 - 2252012年06月-2012年06月 

DOIScopus

詳細

ISSN:11343060

概要:This is an extensive overview of the core and special space-time and Arbitrary Lagrangian-Eulerian (ALE) techniques developed by the authors' research teams for patient-specific cardiovascular fluid-structure interaction (FSI) modeling. The core techniques are the ALE-based variational multiscale (ALE-VMS) method, the Deforming-Spatial-Domain/Stabilized Space-Time formulation, and the stabilized space-time FSI technique. The special techniques include methods for calculating an estimated zero-pressure arterial geometry, prestressing of the blood vessel wall, a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, techniques for using variable arterial wall thickness, mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, a recipe for pre-FSI computations that improve the convergence of the FSI computations, the Sequentially-Coupled Arterial FSI technique and its multiscale versions, techniques for the projection of fluid-structure interface stresses, calculation of the wall shear stress and oscillatory shear index, arterial-surface extraction and boundary condition techniques, and a scaling technique for specifying a more realistic volumetric flow rate. With results from earlier computations, we show how these core and special FSI techniques work in patient-specific cardiovascular simulations. © 2012 CIMNE, Barcelona, Spain.

Comparative patient-specific fsi modeling of cerebral aneurysms

Takizawa, Kenji; Brummer, Tyler; Tezduyar, Tayfun E.; Chen, Peng R.

Proceedings of the 4th International Conference on Computational Methods for Coupled Problems in Science and Engineering, COUPLED PROBLEMS 2011p.590 - 5992011年12月-2011年12月 

Scopus

詳細

概要:We consider a total of ten cases, at three different locations, half of which ruptured sometime after the images were taken. We use the stabilized space-time FSI technique developed by the Team for Advanced Flow Simulation and Modeling, together with a number of special techniques targeting arterial FSI modeling. We compare the ten cases based on the wall shear stress, oscillatory shear index, and the arterial-wall stress. We also investigate how simpler approaches to computer modeling of cerebral aneurysms perform compared to FSI modeling.

ALE-VMS and ST-VMS methods for computer modeling of wind-turbine rotor aerodynamics and fluid-structure interaction

Bazilevs, Yuri; Hsu, Ming Chen; Takizawa, Kenji; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences22(SUPPL.2)2012年08月-2012年08月 

DOIScopus

詳細

ISSN:02182025

概要:We provide an overview of the Arbitrary LagrangianEulerian Variational Multiscale (ALE-VMS) and SpaceTime Variational Multiscale (ST-VMS) methods we have developed for computer modeling of wind-turbine rotor aerodynamics and fluidstructure interaction (FSI). The related techniques described include weak enforcement of the essential boundary conditions, KirchhoffLove shell modeling of the rotor-blade structure, NURBS-based isogeometric analysis, and full FSI coupling. We present results from application of these methods to computer modeling of NREL 5MW and NREL Phase VI wind-turbine rotors at full scale, including comparison with experimental data. © 2012 World Scientific Publishing Company.

Space-time fluid-structure interaction methods

Takizawa, Kenji; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences22(SUPPL.2)2012年08月-2012年08月 

DOIScopus

詳細

ISSN:02182025

概要:Since its introduction in 1991 for computation of flow problems with moving boundaries and interfaces, the Deforming-Spatial-Domain/Stabilized SpaceTime (DSD/SST) formulation has been applied to a diverse set of challenging problems. The classes of problems computed include free-surface and two-fluid flows, fluidobject, fluidparticle and fluidstructure interaction (FSI), and flows with mechanical components in fast, linear or rotational relative motion. The DSD/SST formulation, as a core technology, is being used for some of the most challenging FSI problems, including parachute modeling and arterial FSI. Versions of the DSD/SST formulation introduced in recent years serve as lower-cost alternatives. More recent variational multiscale (VMS) version, which is called DSD/SST-VMST (and also ST-VMS), has brought better computational accuracy and serves as a reliable turbulence model. Special spacetime FSI techniques introduced for specific classes of problems, such as parachute modeling and arterial FSI, have increased the scope and accuracy of the FSI modeling in those classes of computations. This paper provides an overview of the core spacetime FSI technique, its recent versions, and the special spacetime FSI techniques. The paper includes test computations with the DSD/SST-VMST technique. © 2012 World Scientific Publishing Company.

Challenges and directions in computational fluid-structure interaction

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences23(2)p.215 - 2212013年02月-2013年02月 

DOIScopus

詳細

ISSN:02182025

概要:In this lead paper of the special issue, we provide some comments on challenges and directions in computational fluid-structure interaction (FSI). We briefly discuss the significance of computational FSI methods, their components, moving-mesh and nonmoving-mesh methods, mesh moving and remeshing concepts, and FSI coupling techniques. © 2013 World Scientific Publishing Company.

Methods for FSI modeling of spacecraft parachute dynamics and cover separation

Takizawa, Kenji; Montes, Darren; Fritze, Matthew; McIntyre, Spenser; Boben, Joseph; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences23(2)p.307 - 3382013年02月-2013年02月 

DOIScopus

詳細

ISSN:02182025

概要:Fluid-structure interaction (FSI) modeling of spacecraft parachutes involves a number of computational challenges beyond those encountered in a typical FSI problem. The stabilized space-time FSI (SSTFSI) technique serves as a robust and accurate core FSI method, and a number of special FSI methods address the computational challenges specific to spacecraft parachutes. Some spacecraft FSI problems involve even more specific computational challenges and require additional special methods. An example of that is the impulse ejection and parachute extraction of a protective cover used in a spacecraft. The computational challenges specific to this problem are related to the sudden changes in the parachute loads and sudden separation of the cover with very little initial clearance from the spacecraft. We describe the core and special FSI methods, and present the methods we use in FSI analysis of the parachute dynamics and cover separation, including the temporal NURBS representation in modeling the separation motion. © 2013 World Scientific Publishing Company.

Space-time VMS methods for modeling of incompressible flows at high reynolds numbers

Takizawa, Kenji; Montes, Darren; McIntyre, Spenser; Tezduyar, Tayfun E.

Mathematical Models and Methods in Applied Sciences23(2)p.223 - 2482013年02月-2013年02月 

DOIScopus

詳細

ISSN:02182025

概要:Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation was developed for flow problems with moving interfaces and has been successfully applied to some of the most complex problems in that category. A new version of the DSD/SST method for incompressible flows, which has additional subgrid-scale representation features, is the space-time version of the residual-based variational multiscale (VMS) method. This new version, called DSD/SST-VMST and also Space-Time VMS (ST-VMS), provides a more comprehensive framework for the VMS method. We describe the ST-VMS method, including the embedded stabilization parameters, and assess its performance in computation of flow problems at high Reynolds numbers by comparing the results to experimental data. The computations, which include those with 3D airfoil geometries and spacecraft configurations, signal a promising future for the ST-VMS method. © 2013 World Scientific Publishing Company.

Patient-specific computational analysis of the influence of a stent on the unsteady flow in cerebral aneurysms

Takizawa, Kenji; Schjodt, Kathleen; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

Computational Mechanics51(6)p.1061 - 10732013年06月-2013年06月 

DOIScopus

詳細

ISSN:01787675

概要:We present a patient-specific computational analysis of the influence of a stent on the unsteady flow in cerebral aneurysms. The analysis is based on four different arterial models extracted form medical images, and the stent is placed across the neck of the aneurysm to reduce the flow circulation in the aneurysm. The core computational technique used in the analysis is the space-time (ST) version of the variational multiscale (VMS) method and is called "DSD/SST-VMST". The special techniques developed for this class of cardiovascular fluid mechanics computations are used in conjunction with the DSD/SST-VMST technique. The special techniques include NURBS representation of the surface over which the stent model and mesh are built, mesh generation with a reasonable resolution across the width of the stent wire and with refined layers of mesh near the arterial and stent surfaces, modeling the double-stent case, and quantitative assessment of the flow circulation in the aneurysm. We provide a brief overview of the special techniques, compute the unsteady flow patterns in the aneurysm for the four arterial models, and investigate in each case how those patterns are influenced by the presence of single and double stents. © 2012 Springer-Verlag.

Computer modeling techniques for flapping-wing aerodynamics of a locust

Takizawa, Kenji; Henicke, Bradley; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

Computers and Fluids85p.125 - 1342013年10月-2013年10月 

DOIScopus

詳細

ISSN:00457930

概要:We present an overview of the special computer modeling techniques we have developed recently for flapping-wing aerodynamics of a locust. The wing motion and deformation data is from an actual locust, extracted from high-speed, multi-camera video recordings of the locust in a wind tunnel. The special techniques have been developed around our core computational technique, which is the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation. Here we use the version of the DSD/SST formulation derived in conjunction with the variational multiscale (VMS) method, and this version is called "DSD/SST-VMST." The special techniques are based on using, in the space-time flow computations, NURBS basis functions for the temporal representation of the motion and deformation of the locust wings. Temporal NURBS basis functions are used also in representation of the motion of the volume meshes computed and in remeshing. In this special-issue paper, we present a condensed version of the material from [1], concentrating on the flapping-motion modeling and computations, and also a temporal-order study from [2]. © 2012 Elsevier Ltd.

Patient-Specific Computational Fluid Mechanics of Cerebral Arteries with Aneurysm and Stent

Takizawa, Kenji; Schjodt, Kathleen; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

Multiscale Simulations and Mechanics of Biological Materialsp.119 - 1472013年03月-2013年03月 

DOIScopus

詳細

概要:We present patient-specific computational fluid mechanics analysis of blood flow in cerebral arteries with aneurysm and stent. The special arterial fluid mechanics techniques we have developed for this are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using a nonuniform rational basis spline for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stents. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents. We also compare the flow patterns obtained with the finite- and zero-thickness representations of the stent. This edition first published 2013 © 2013 John Wiley & Sons, Ltd.

Computational fluid mechanics and fluid-structure interaction

Takizawa, Kenji; Bazilevs, Yuri; Tezduyar, Tayfun E.

Computational Mechanics50(6)2012年09月-2012年09月 

DOIScopus

詳細

ISSN:01787675

Fluid-structure interaction modeling of ringsail parachutes with disreefing and modified geometric porosity

Takizawa, Kenji; Fritze, Matthew; Montes, Darren; Spielman, Timothy; Tezduyar, Tayfun E.

Computational Mechanics50(6)p.835 - 8542012年08月-2012年08月 

DOIScopus

詳細

ISSN:01787675

概要:Fluid-structure interaction (FSI) modeling of parachutes poses a number of computational challenges. These include the lightness of the parachute canopy compared to the air masses involved in the parachute dynamics, in the case of ringsail parachutes the geometric porosity created by the construction of the canopy from "rings" and "sails" with hundreds of "ring gaps" and "sail slits," in the case of parachute clusters the contact between the parachutes, and "disreefing" from one stage to another when the parachute is used in multiple stages. The Team for Advanced Flow Simulation and Modeling (Ta*AFSM) has been successfully addressing these computational challenges with the Stabilized Space-Time FSI (SSTFSI) technique, which was developed and improved over the years by the Ta*AFSM and serves as the core numerical technology, and a number of special techniques developed in conjunction with the SSTFSI technique. The quasi-direct and direct coupling techniques developed by the Ta*AFSM, which are applicable to cases with nonmatching fluid and structure meshes at the interface, yield more robust algorithms for FSI computations where the structure is light. The special technique used in dealing with the geometric complexities of the rings and sails is the homogenized modeling of geometric porosity (HMGP), which was developed and improved in recent years by the Ta*AFSM. The surface-edge-node contact tracking (SENCT) technique was introduced by the Ta*AFSM as a contact algorithm where the objective is to prevent the structural surfaces from coming closer than a minimum distance in an FSI computation. The recently-introduced conservative version of the SENCT technique is more robust and is now an essential technology in the parachute cluster computations carried out by the Ta*AFSM. As an additional computational challenge, the parachute canopy might, by design, have some of its panels and sails removed. In FSI computation of parachutes with such "modified geometric porosity," the flow through the "windows" created by the removal of the panels and the wider gaps created by the removal of the sails cannot be accurately modeled with the HMGP and needs to be actually resolved during the FSI computation. In this paper we focus on parachute disreefing, including the disreefing of parachute clusters, and parachutes with modified geometric porosity, including the reefed stages of such parachutes. We describe the additional special techniques we have developed to address the challenges involved and report FSI computations for parachutes and parachute clusters with disreefing and modified geometric porosity. © 2012 Springer-Verlag.

Space-time computational analysis of bio-inspired flapping-wing aerodynamics of a micro aerial vehicle

Takizawa, Kenji; Kostov, Nikolay; Puntel, Anthony; Henicke, Bradley; Tezduyar, Tayfun E.

Computational Mechanics50(6)p.761 - 7782012年08月-2012年08月 

DOIScopus

詳細

ISSN:01787675

概要:We present a detailed computational analysis of bio-inspired flapping-wing aerodynamics of a micro aerial vehicle (MAV). The computational techniques used include the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation, which serves as the core computational technique. The DSD/SST formulation is a moving-mesh technique, and in the computations reported here we use the space-time version of the residual-based variational multiscale (VMS) method, which is called "DSD/ SST-VMST." The motion and deformation of the wings are based on data extracted from the high-speed, multi-camera video recordings of a locust in a wind tunnel. A set of special space-time techniques are also used in the computations in conjunction with the DSD/SST method. The special techniques are based on using, in the space-time flow computations, NURBS basis functions for the temporal representation of the motion and deformation of the wings and for the mesh moving and remeshing. The computational analysis starts with the computation of the base case, and includes computations with increased temporal and spatial resolutions compared to the base case. In increasing the temporal resolution, we separately test increasing the temporal order, the number of temporal subdivisions, and the frequency of remeshing. In terms of the spatial resolution, we separately test increasing the wing-mesh refinement in the normal and tangential directions and changing the way node connectivities are handled at the wingtips. The computational analysis also includes using different combinations of wing configurations for the MAV and investigating the beneficial and disruptive interactions between the wings and the role of wing camber and twist. © 2012 Springer-Verlag.

Space-time techniques for computational aerodynamics modeling of flapping wings of an actual locust

Takizawa, Kenji; Henicke, Bradley; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

Computational Mechanics50(6)p.743 - 7602012年08月-2012年08月 

DOIScopus

詳細

ISSN:01787675

概要:We present the special space-time computational techniques we have introduced recently for computational aerodynamics modeling of flapping wings of an actual locust. These techniques have been designed to be used with the deforming-spatial-domain/stabilized space-time (DSD/SST) formulation, which is the core computational technique. The DSD/SST formulation was developed for flow problems with moving interfaces and was elevated to newer versions over the years, including the space-time version of the residual-based variational multiscale (VMS) method, which is called "DSD/SST-VMST" and used in the computations reported here. The special space-time techniques are based on using, in the space-time flow computations, NURBS basis functions for the temporal representation of the motion and deformation of the locust wings. The motion and deformation data is extracted from the high-speed, multi-camera video recordings of a locust in a wind tunnel. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. These ingredients provide an accurate and efficient way of dealing with the wind tunnel data and the mesh. The computations demonstrate the effectiveness of the core and special space-time techniques in modeling the aerodynamics of flapping wings, with the wing motion and deformation coming from an actual locust. © 2012 Springer-Verlag.

Patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent

Takizawa, Kenji; Schjodt, Kathleen; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

Computational Mechanics50(6)p.675 - 6862012年08月-2012年08月 

DOIScopus

詳細

ISSN:01787675

概要:We present the special arterial fluid mechanics techniques we have developed for patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent. These techniques are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stent. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents. We also compare the flow patterns obtained with the finite- and zero-thickness representations of the stent. © 2012 Springer-Verlag.

Fluid-structure interaction modeling of clusters of spacecraft parachutes with modified geometric porosity

Takizawa, Kenji; Tezduyar, Tayfun E.; Boben, Joseph; Kostov, Nikolay; Boswell, Cody; Buscher, Austin

Computational Mechanics52(6)p.1351 - 13642013年12月-2013年12月 

DOIScopus

詳細

ISSN:01787675

概要:To increase aerodynamic performance, the geometric porosity of a ringsail spacecraft parachute canopy is sometimes increased, beyond the "rings" and "sails" with hundreds of "ring gaps" and "sail slits." This creates extra computational challenges for fluid-structure interaction (FSI) modeling of clusters of such parachutes, beyond those created by the lightness of the canopy structure, geometric complexities of hundreds of gaps and slits, and the contact between the parachutes of the cluster. In FSI computation of parachutes with such "modified geometric porosity," the flow through the "windows" created by the removal of the panels and the wider gaps created by the removal of the sails cannot be accurately modeled with the Homogenized Modeling of Geometric Porosity (HMGP), which was introduced to deal with the hundreds of gaps and slits. The flow needs to be actually resolved. All these computational challenges need to be addressed simultaneously in FSI modeling of clusters of spacecraft parachutes with modified geometric porosity. The core numerical technology is the Stabilized Space-Time FSI (SSTFSI) technique, and the contact between the parachutes is handled with the Surface-Edge-Node Contact Tracking (SENCT) technique. In the computations reported here, in addition to the SSTFSI and SENCT techniques and HMGP, we use the special techniques we have developed for removing the numerical spinning component of the parachute motion and for restoring the mesh integrity without a remesh. We present results for 2- and 3-parachute clusters with two different payload models. © 2013 Springer-Verlag Berlin Heidelberg.

Computational Fluid-Structure Interaction: Methods and Applications

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Fluid-Structure Interaction: Methods and Applications2012年12月-2012年12月 

DOIScopus

詳細

概要:Computational Fluid-Structure Interaction: Methods and Applications takes the reader from the fundamentals of computational fluid and solid mechanics to the state-of-the-art in computational FSI methods, special FSI techniques, and solution of real-world problems. Leading experts in the field present the material using a unique approach that combines advanced methods, special techniques, and challenging applications. This book begins with the differential equations governing the fluid and solid mechanics, coupling conditions at the fluid-solid interface, and the basics of the finite element method. It continues with the ALE and space-time FSI methods, spatial discretization and time integration strategies for the coupled FSI equations, solution techniques for the fully-discretized coupled equations, and advanced FSI and space-time methods. It ends with special FSI techniques targeting cardiovascular FSI, parachute FSI, and wind-turbine aerodynamics and FSI. Key features: First book to address the state-of-the-art in computational FSI Combines the fundamentals of computational fluid and solid mechanics, the state-of-the-art in FSI methods, and special FSI techniques targeting challenging classes of real-world problems Covers modern computational mechanics techniques, including stabilized, variational multiscale, and space-time methods, isogeometric analysis, and advanced FSI coupling methods. Is in full color, with diagrams illustrating the fundamental concepts and advanced methods and with insightful visualization illustrating the complexities of the problems that can be solved with the FSI methods covered in the book. Authors are award winning, leading global experts in computational FSI, who are known for solving some of the most challenging FSI problems. Computational Fluid-Structure Interaction: Methods and Applications is a comprehensive reference for researchers and practicing engineers who would like to advance their existing knowledge on these subjects. It is also an ideal text for graduate and senior-level undergraduate courses in computational fluid mechanics and computational FSI. © 2013 John Wiley & Sons, Ltd.

Space-time computation techniques with continuous representation in time (ST-C)

Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Mechanics53(1)p.91 - 992014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:We introduce space-time computation techniques with continuous representation in time (ST-C), using temporal NURBS basis functions. This gives us a temporally smooth, NURBS-based solution, which is desirable in some cases, and a more efficient way of dealing with the computed data. We propose two versions of ST-C. In the first version, the smooth solution is extracted by projection from a solution computed with a different temporal representation, typically a discontinuous one. We use a successive projection technique with a small number of temporal NURBS basis functions at each projection, and therefore the extraction can take place as the solution with discontinuous temporal representation is being computed, without storing a large amount of time-history data. This version is not limited to solutions computed with ST techniques. In the second version, the solution with continuous temporal representation is computed directly by using a small number of temporal NURBS basis functions in the variational formulation associated with each time step. © 2013 Springer-Verlag Berlin Heidelberg.

Space-time VMS computation of wind-turbine rotor and tower aerodynamics

Takizawa, Kenji; Tezduyar, Tayfun E.; McIntyre, Spenser; Kostov, Nikolay; Kolesar, Ryan; Habluetzel, Casey

Computational Mechanics53(1)p.1 - 152014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:We present the space-time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of flows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational flexibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion. © 2013 Springer-Verlag Berlin Heidelberg.

Space–time interface-tracking with topology change (ST-TC)

Takizawa, Kenji; Tezduyar, Tayfun E.; Buscher, Austin; Asada, Shohei

Computational Mechanics54(4)p.955 - 9712014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2013, Springer-Verlag Berlin Heidelberg. To address the computational challenges associated with contact between moving interfaces, such as those in cardiovascular fluid–structure interaction (FSI), parachute FSI, and flapping-wing aerodynamics, we introduce a space–time (ST) interface-tracking method that can deal with topology change (TC). In cardiovascular FSI, our primary target is heart valves. The method is a new version of the deforming-spatial-domain/stabilized space–time (DSD/SST) method, and we call it ST-TC. It includes a master–slave system that maintains the connectivity of the “parent” mesh when there is contact between the moving interfaces. It is an efficient, practical alternative to using unstructured ST meshes, but without giving up on the accurate representation of the interface or consistent representation of the interface motion. We explain the method with conceptual examples and present 2D test computations with models representative of the classes of problems we are targeting.

Computational engineering analysis with the new-generation space-time methods

Takizawa, Kenji

Computational Mechanics54(2)p.193 - 2112014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:This is an overview of the new directions we have taken the space-time (ST) methods in bringing solution and analysis to different classes of computationally challenging engineering problems. The classes of problems we have focused on include bio-inspired flapping-wing aerodynamics, wind-turbine aerodynamics, and cardiovascular fluid mechanics. The new directions for the ST methods include the variational multiscale version of the Deforming-Spatial- Domain/Stabilized ST method, using NURBS basis functions in temporal representation of the unknown variables and motion of the solid surfaces and fluid meshes, ST techniques with continuous representation in time, and ST interface-tracking with topology change. We describe the new directions and present examples of the challenging problems solved. © 2014 Springer-Verlag Berlin Heidelberg.

Sequentially-coupled space-time FSI analysis of bio-inspired flapping-wing aerodynamics of an MAV

Takizawa, Kenji; Tezduyar, Tayfun E.; Kostov, Nikolay

Computational Mechanics54(2)p.213 - 2332014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:We present a sequentially-coupled space-time (ST) computational fluid-structure interaction (FSI) analysis of flapping-wing aerodynamics of a micro aerial vehicle (MAV). The wing motion and deformation data, whether prescribed fully or partially, is from an actual locust, extracted from high-speed, multi-camera video recordings of the locust in a wind tunnel. The core computational FSI technology is based on the Deforming-Spatial-Domain/ Stabilized ST (DSD/SST) formulation. This is supplemented with using NURBS basis functions in temporal representation of the wing and mesh motion, and in remeshing. Here we use the version of the DSD/SST formulation derived in conjunction with the variational multiscale (VMS) method, and this version is called "DSD/SST-VMST." The structural mechanics computations are based on the Kirchhoff-Love shell model. The sequential-coupling technique is applicable to some classes of FSI problems, especially those with temporally-periodic behavior. We show that it performs well in FSI computations of the flapping-wing aerodynamics we consider here. In addition to the straight-flight case, we analyze cases where the MAV body has rolling, pitching, or rolling and pitching motion. We study how all these influence the lift and thrust. © 2014 Springer-Verlag Berlin Heidelberg.

ST and ALE-VMS methods for patient-specific cardiovascular fluid mechanics modeling

Takizawa, Kenji; Bazilevs, Yuri; Tezduyar, Tayfun E.; Long, Christopher C.; Marsden, Alison L.; Schjodt, Kathleen

Mathematical Models and Methods in Applied Sciences24(12)p.2437 - 24862014年01月-2014年01月 

DOIScopus

詳細

ISSN:02182025

概要:This paper provides a review of the space-time (ST) and Arbitrary Lagrangian-Eulerian (ALE) techniques developed by the first three authors' research teams for patient-specific cardiovascular fluid mechanics modeling, including fluid-structure interaction (FSI). The core methods are the ALE-based variational multiscale (ALE-VMS) method, the Deforming-Spatial-Domain/Stabilized ST formulation, and the stabilized ST FSI technique. A good number of special techniques targeting cardiovascular fluid mechanics have been developed to be used with the core methods. These include: (i) arterial-surface extraction and boundary condition techniques, (ii) techniques for using variable arterial wall thickness, (iii) methods for calculating an estimated zero-pressure arterial geometry, (iv) techniques for prestressing of the blood vessel wall, (v) mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, (vi) a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, (vii) a scaling technique for specifying a more realistic volumetric flow rate, (viii) techniques for the projection of fluid-structure interface stresses, (ix) a recipe for pre-FSI computations that improve the convergence of the FSI computations, (x) the Sequentially-Coupled Arterial FSI technique and its multiscale versions, (xi) techniques for calculation of the wall shear stress (WSS) and oscillatory shear index (OSI), (xii) methods for stent modeling and mesh generation, (xiii) methods for calculation of the particle residence time, and (xiv) methods for an estimated element-based zero-stress state for the artery. Here we provide an overview of the special techniques for WSS and OSI calculations, stent modeling and mesh generation, and calculation of the residence time with application to pulsatile ventricular assist device (PVAD). We provide references for some of the other special techniques. With results from earlier computations, we show how these core and special techniques work. © 2014 World Scientific Publishing Company.

FSI modeling of the reefed stages and disreefing of the Orion spacecraft parachutes

Takizawa, Kenji; Tezduyar, Tayfun E.; Boswell, Cody; Kolesar, Ryan; Montel, Kenneth

Computational Mechanics54(5)p.1203 - 12202014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg. Orion spacecraft main and drogue parachutes are used in multiple stages, starting with a “reefed” stage where a cable along the parachute skirt constrains the diameter to be less than the diameter in the subsequent stage. After a period of time during the descent, the cable is cut and the parachute “disreefs” (i.e. expands) to the next stage. Fluid–structure interaction (FSI) modeling of the reefed stages and disreefing involve computational challenges beyond those in FSI modeling of fully-open spacecraft parachutes. These additional challenges are created by the increased geometric complexities and by the rapid changes in the parachute geometry during disreefing. The computational challenges are further increased because of the added geometric porosity of the latest design of the Orion spacecraft main parachutes. The “windows” created by the removal of panels compound the geometric and flow complexity. That is because the Homogenized Modeling of Geometric Porosity, introduced to deal with the flow through the hundreds of gaps and slits involved in the construction of spacecraft parachutes, cannot accurately model the flow through the windows, which needs to be actually resolved during the FSI computation. In parachute FSI computations, the resolved geometric porosity is significantly more challenging than the modeled geometric porosity, especially in computing the reefed stages and disreefing. Orion spacecraft main and drogue parachutes will both have three stages, with computation of the Stage 1 shape and disreefing from Stage 1 to Stage 2 for the main parachute being the most challenging because of the lowest “reefing ratio” (the ratio of the reefed skirt diameter to the nominal diameter). We present the special modeling techniques and strategies we devised to address the computational challenges encountered in FSI modeling of the reefed stages and disreefing of the main and drogue parachutes. We report, for a single parachute, FSI computation of both reefed stages and both disreefing events for both the main and drogue parachutes. In the case of the main parachute, we also report, for a 2-parachute cluster, FSI computation of the disreefing from Stage 2 to Stage 3. With results from these computations, we demonstrate that we have to a great extent overcome one of the most formidable challenges in FSI modeling of spacecraft parachutes.

A variational multiscale method for particle-cloud tracking in turbomachinery flows

Corsini, A.; Rispoli, F.; Sheard, A. G.; Takizawa, K.; Tezduyar, T. E.; Venturini, P.

Computational Mechanics54(5)p.1191 - 12022014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg. We present a computational method for simulation of particle-laden flows in turbomachinery. The method is based on a stabilized finite element fluid mechanics formulation and a finite element particle-cloud tracking method. We focus on induced-draft fans used in process industries to extract exhaust gases in the form of a two-phase fluid with a dispersed solid phase. The particle-laden flow causes material wear on the fan blades, degrading their aerodynamic performance, and therefore accurate simulation of the flow would be essential in reliable computational turbomachinery analysis and design. The turbulent-flow nature of the problem is dealt with a Reynolds-Averaged Navier–Stokes model and Streamline-Upwind/Petrov–Galerkin/Pressure-Stabilizing/Petrov–Galerkin stabilization, the particle-cloud trajectories are calculated based on the flow field and closure models for the turbulence–particle interaction, and one-way dependence is assumed between the flow field and particle dynamics. We propose a closure model utilizing the scale separation feature of the variational multiscale method, and compare that to the closure utilizing the eddy viscosity model. We present computations for axial- and centrifugal-fan configurations, and compare the computed data to those obtained from experiments, analytical approaches, and other computational methods.

Biomedical fluid mechanics and fluid–structure interaction

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.

Computational Mechanics54(4)2014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

Space–time fluid mechanics computation of heart valve models

Takizawa, Kenji; Tezduyar, Tayfun E.; Buscher, Austin; Asada, Shohei

Computational Mechanics54(4)p.973 - 9862014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg. Fluid mechanics computation of heart valves with an interface-tracking (moving-mesh) method was one of the classes of computations targeted in introducing the space–time (ST) interface tracking method with topology change (ST-TC). The ST-TC method is a new version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method. It can deal with an actual contact between solid surfaces in flow problems with moving interfaces, while still possessing the desirable features of interface-tracking methods, such as better resolution of the boundary layers. The DSD/SST method with effective mesh update can already handle moving-interface problems when the solid surfaces are in near contact or create near TC, if the “nearness” is sufficiently “near” for the purpose of solving the problem. That, however, is not the case in fluid mechanics of heart valves, as the solid surfaces need to be brought into an actual contact when the flow has to be completely blocked. Here we extend the ST-TC method to 3D fluid mechanics computation of heart valve models. We present computations for two models: an aortic valve with coronary arteries and a mechanical aortic valve. These computations demonstrate that the ST-TC method can bring interface-tracking accuracy to fluid mechanics of heart valves, and can do that with computational practicality.

Estimation of element-based zero-stress state for arterial FSI computations

Takizawa, Kenji; Takagi, Hirokazu; Tezduyar, Tayfun E.; Torii, Ryo

Computational Mechanics54(4)p.895 - 9102014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2013, Springer-Verlag Berlin Heidelberg. In patient-specific arterial fluid–structure interaction (FSI) computations the image-based arterial geometry comes from a configuration that is not stress-free. We present a method for estimation of element-based zero-stress (ZS) state. The method has three main components. (1) An iterative method, which starts with an initial guess for the ZS state, is used for computing the element-based ZS state such that when a given pressure load is applied, the image-based target shape is matched. (2) A method for straight-tube geometries with single and multiple layers is used for computing the element-based ZS state so that we match the given diameter and longitudinal stretch in the target configuration and the “opening angle.” (3) An element-based mapping between the arterial and straight-tube configurations is used for mapping from the arterial configuration to the straight-tube configuration, and for mapping the estimated ZS state of the straight tube back to the arterial configuration, to be used as the initial guess for the iterative method that matches the image-based target shape. We present a set of test computations to show how the method works.

Coronary arterial dynamics computation with medical-image-based time-dependent anatomical models and element-based zero-stress state estimates

Takizawa, Kenji; Torii, Ryo; Takagi, Hirokazu; Tezduyar, Tayfun E.; Xu, Xiao Y.

Computational Mechanics54(4)p.1047 - 10532014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2014, The Author(s). We propose a method for coronary arterial dynamics computation with medical-image-based time-dependent anatomical models. The objective is to improve the computational analysis of coronary arteries for better understanding of the links between the atherosclerosis development and mechanical stimuli such as endothelial wall shear stress and structural stress in the arterial wall. The method has two components. The first one is element-based zero-stress (ZS) state estimation, which is an alternative to prestress calculation. The second one is a “mixed ZS state” approach, where the ZS states for different elements in the structural mechanics mesh are estimated with reference configurations based on medical images coming from different instants within the cardiac cycle. We demonstrate the robustness of the method in a patient-specific coronary arterial dynamics computation where the motion of a thin strip along the arterial surface and two cut surfaces at the arterial ends is specified to match the motion extracted from the medical images.

Aerodynamic and FSI Analysis of Wind Turbines with the ALE-VMS and ST-VMS Methods

Bazilevs, Yuri; Takizawa, Kenji; Tezduyar, Tayfun E.; Hsu, Ming Chen; Kostov, Nikolay; McIntyre, Spenser

Archives of Computational Methods in Engineering21(4)p.359 - 3982014年01月-2014年01月 

DOIScopus

詳細

ISSN:11343060

概要:© 2014, CIMNE, Barcelona, Spain. We provide an overview of the aerodynamic and FSI analysis of wind turbines the first three authors’ teams carried out in recent years with the ALE-VMS and ST-VMS methods. The ALE-VMS method is the variational multiscale version of the Arbitrary Lagrangian–Eulerian (ALE) method. The VMS components are from the residual-based VMS (RBVMS) method. The ST-VMS method is the VMS version of the deforming-spatial-domain/stabilized space–time (DSD/SST) method. The techniques complementing these core methods include weak enforcement of the essential boundary conditions, NURBS-based isogeometric analysis, using NURBS basis functions in temporal representation of the rotor motion, mesh motion and also in remeshing, rotation representation with constant angular velocity, Kirchhoff–Love shell modeling of the rotor-blade structure, and full FSI coupling. The analysis cases include the aerodynamics of standalone wind-turbine rotors, wind-turbine rotor and tower, and the FSI that accounts for the deformation of the rotor blades. The specific wind turbines considered are NREL 5MW, NREL Phase VI and Micon 65/13M, all at full scale, and our analysis for NREL Phase VI and Micon 65/13M includes comparison with the experimental data.

Engineering Analysis and Design with ALE-VMS and Space–Time Methods

Takizawa, Kenji; Bazilevs, Yuri; Tezduyar, Tayfun E.; Hsu, Ming Chen; Øiseth, Ole; Mathisen, Kjell M.; Kostov, Nikolay; McIntyre, Spenser

Archives of Computational Methods in Engineering21(4)p.481 - 5082014年01月-2014年01月 

DOIScopus

詳細

ISSN:11343060

概要:© 2014, CIMNE, Barcelona, Spain. Flow problems with moving boundaries and interfaces include fluid–structure interaction (FSI) and a number of other classes of problems, have an important place in engineering analysis and design, and offer some formidable computational challenges. Bringing solution and analysis to them motivated the Deforming-Spatial-Domain/Stabilized Space–Time (DSD/SST) method and also the variational multiscale version of the Arbitrary Lagrangian–Eulerian method (ALE-VMS). Since their inception, these two methods and their improved versions have been applied to a diverse set of challenging problems with a common core computational technology need. The classes of problems solved include free-surface and two-fluid flows, fluid–object and fluid–particle interaction, FSI, and flows with solid surfaces in fast, linear or rotational relative motion. Some of the most challenging FSI problems, including parachute FSI, wind-turbine FSI and arterial FSI, are being solved and analyzed with the DSD/SST and ALE-VMS methods as core technologies. Better accuracy and improved turbulence modeling were brought with the recently-introduced VMS version of the DSD/SST method, which is called DSD/SST-VMST (also ST-VMS). In specific classes of problems, such as parachute FSI, arterial FSI, ship hydrodynamics, fluid–object interaction, aerodynamics of flapping wings, and wind-turbine aerodynamics and FSI, the scope and accuracy of the FSI modeling were increased with the special ALE-VMS and ST FSI techniques targeting each of those classes of problems. This article provides an overview of the core ALE-VMS and ST FSI techniques, their recent versions, and the special ALE-VMS and ST FSI techniques. It also provides examples of challenging problems solved and analyzed in parachute FSI, arterial FSI, ship hydrodynamics, aerodynamics of flapping wings, wind-turbine aerodynamics, and bridge-deck aerodynamics and vortex-induced vibrations.

Multiscale methods for gore curvature calculations from FSI modeling of spacecraft parachutes

Takizawa, Kenji; Tezduyar, Tayfun E.; Kolesar, Ryan; Boswell, Cody; Kanai, Taro; Montel, Kenneth

Computational Mechanics54(6)p.1461 - 14762014年01月-2014年01月 

DOIScopus

詳細

ISSN:01787675

概要:© 2014, Springer-Verlag Berlin Heidelberg. There are now some sophisticated and powerful methods for computer modeling of parachutes. These methods are capable of addressing some of the most formidable computational challenges encountered in parachute modeling, including fluid–structure interaction (FSI) between the parachute and air flow, design complexities such as those seen in spacecraft parachutes, and operational complexities such as use in clusters and disreefing. One should be able to extract from a reliable full-scale parachute modeling any data or analysis needed. In some cases, however, the parachute engineers may want to perform quickly an extended or repetitive analysis with methods based on simplified models. Some of the data needed by a simplified model can very effectively be extracted from a full-scale computer modeling that serves as a pilot. A good example of such data is the circumferential curvature of a parachute gore, where a gore is the slice of the parachute canopy between two radial reinforcement cables running from the parachute vent to the skirt. We present the multiscale methods we devised for gore curvature calculation from FSI modeling of spacecraft parachutes. The methods include those based on the multiscale sequentially-coupled FSI technique and using NURBS meshes. We show how the methods work for the fully-open and two reefed stages of the Orion spacecraft main and drogue parachutes.

Fluid–structure interaction modeling of patient-specific cerebral aneurysms

Takizawa, Kenji; Tezduyar, Tayfun E.

Lecture Notes in Computational Vision and Biomechanics12p.25 - 452014年01月-2014年01月 

DOIScopus

詳細

ISSN:22129391

概要:© Springer Science+Business Media Dordrecht 2014. We provide an overview of the special techniques developed earlier by the Team for Advanced Flow Simulation and Modeling (TwAFSM) for fluid–structure interaction (FSI) modeling of patient-specific cerebral aneurysms. The core FSI techniques are the Deforming-Spatial-Domain/Stabilized Space– Time formulation and the stabilized space–time FSI technique. The special techniques include techniques for calculating an estimated zero-pressure arterial geometry, a special mapping technique for specifying the velocity profile at an inflow boundary with non-circular shape, techniques for using variable arterial wall thickness, mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, a recipe for pre-FSI computations that improve the convergence of the FSI computations, techniques for calculation of the wall shear stress and oscillatory shear index, and arterial-surface extraction and boundary condition techniques. We show, with results from earlier computations, how these techniques work. We also describe the arterial FSI techniques developed and implemented recently by the TwAFSM and present a sample from a wide set of patient-specific cerebral-aneurysm models we computed recently.

書籍等出版物

CIP法とJavaによるCGシミュレーション

矢部 孝, 尾形 陽一, 滝沢 研二

森北出版2007年 02月-

詳細

ISBN:978-4-627-91911-2

Computational fluid-structure interaction: Methods and applications

Y. Bazilevs, K. Takizawa, and T.E. Tezduyar

John Wiley2013年 02月-

詳細

ISBN:978-0-470-97877-1

外部研究資金

科学研究費採択状況

研究種別:

高次精度パラメトリック時空間モデルによる機械と流体の相互作用解析手法の開発

2012年-0月-2015年-0月

配分額:¥4550000

研究種別:

多モーメント手法による多目的CFDコアの開発

配分額:¥18200000

研究種別:

荒天下を航走する船舶の動揺ならびに船体弾性応答計算法の研究開発

配分額:¥48100000

研究種別:

赤血球の運動に着目した開閉する心臓弁の流体構造連成解析手法の構築

2018年-0月-2023年-0月

配分額:¥43420000

研究種別:

周期的定常流れに対する4次元流れ領域区分の定式化および数値解析法の提案

2016年-0月-2018年-0月

配分額:¥3250000

研究種別:

ものづくり流体アプリケーションのエクサスケールへの進化

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配分額:¥10920000

研究種別:

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2014年-0月-2019年-0月

配分額:¥188370000

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Seminars on Applied Mechanics of Fluid-Structure Interactions C大学院創造理工学研究科2019春学期
流体構造連成系応用力学演習C大学院創造理工学研究科2019春学期
Seminars on Applied Mechanics of Fluid-Structure Interactions D大学院創造理工学研究科2019秋学期
流体構造連成系応用力学演習D大学院創造理工学研究科2019秋学期
Seminar on Fluid Mechanics of Computational Analysis A大学院創造理工学研究科2019春学期
Seminar on Fluid Mechanics of Computational Analysis A大学院創造理工学研究科2019春学期
Seminar on Fluid Mechanics of Computational Analysis B大学院創造理工学研究科2019秋学期
Seminar on Fluid Mechanics of Computational Analysis B大学院創造理工学研究科2019秋学期
Seminar on Fluid Mechanics of Computational Analysis C大学院創造理工学研究科2019春学期
Seminar on Fluid Mechanics of Computational Analysis C大学院創造理工学研究科2019春学期
Seminar on Fluid Mechanics of Computational Analysis D大学院創造理工学研究科2019秋学期
Seminar on Fluid Mechanics of Computational Analysis D大学院創造理工学研究科2019秋学期
Master's Thesis (Department of Modern Mechanical Engineering)大学院創造理工学研究科2019通年
Fluid Mechanics of Computing大学院基幹理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院基幹理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院創造理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院創造理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院創造理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院先進理工学研究科2019集中講義(春学期)
Fluid Mechanics of Computing大学院先進理工学研究科2019集中講義(春学期)
流体構造連成系応用力学研究大学院創造理工学研究科2019通年
Research on Fluid Mechanics of Computational Analysis大学院創造理工学研究科2019通年