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研究種別：

2012年-0月-2014年-0月

配分額：￥910000

2016年度共同研究者：T. P. Witelski

研究成果概要：We have considered self-similar sign-changing solutions to the thin-film equation on a semi-infinite domain with ze...We have considered self-similar sign-changing solutions to the thin-film equation on a semi-infinite domain with zero-pressure-type boundary conditions imposed at the fixed boundary.  In particular, we have identified classes of both first- and second-kind compactly supported self-similar solutions and have explained how these solutions interact as parameters vary.  

2018年度共同研究者：L. Smolka, T. P. Witelski

研究成果概要：1) Working with Professor T P Witelski (Duke University, USA), we have been studying out-diffusion solutions of the...1) Working with Professor T P Witelski (Duke University, USA), we have been studying out-diffusion solutions of the so-called thin film equation (a fourth order parabolic partial differential equation) on a finite multi-dimensional domain; this extends our recent previous work on the one-dimensional problem.While considering this problem, we decided first to make a preliminary study of the related problem for the lower (second) order porous medium equation.  In this context, we have constructed analytically self-similar solutions that act as large time attractors for solutions defined on sectorial [quarter, half-plane and three-quarter-plane] domains.  We have confirmed these results using numerical simulations.2) While working on this project, I established a new working relationship with Professor L. Smolka (Bucknell University, USA) looking at how thin films evolve in a periodic domain (corresponding physically to the external surface of a cylinder) under the combined effects  of gravity (drainage) and thermal stresses (leading to a non-convex convective flux of fluid).  The interaction of convective effects and surface tension (fourth order parabolic terms) yields solutions containing non-classical shock dynamics, such as undercompressive-compressive shock pairs and undercompressive shocks-rarefaction fans.  We are currently writing up the results of this research for publication in the near future.

2019年度

研究成果概要：We have been analytically and computationally investigating the motion of a monolayer thin film (tether) held betwe...We have been analytically and computationally investigating the motion of a monolayer thin film (tether) held between two quasi-steady masses.  The monolayer tether is assumed to be stretched by an externally imposed symmetric stagnation point flow and interesting dynamics arise due to the competition between surface tension and convective flow.  In particular, we have been interested in whether the tether breaks in finite time and how such rupture occurs.Mathematical modelling of this phenomena leads to a higher-order non-autonomous nonlinear diffusion-convection equation containing a parameter that takes different values depending on the thickness of the monolayer film.We have analysed the behaviour of the evolution equation for general values of the parameter and have identified that for large enough values of the parameter rupture of the tether does not occur in finite time.We are now writing this research up for publication in the near future.

2015年度共同研究者：Thomas Witelski

研究成果概要：Working with an international collaborator, I have investigated the dynamics of a thin liquid film draining off of ...Working with an international collaborator, I have investigated the dynamics of a thin liquid film draining off of one edge of a flat substrate. Such a scenario frequently arises in the natural sciences, engineering and industry. We have also extended these results to the (non-physical) case where the solution (corresponding to film height) can change sign. The analytical results are supported by detailed numerical calculations.

2017年度共同研究者：T. P. Witelski

研究成果概要：Working with Professor T. P. Witekski (Duke University, USA), we mathematically investigated the dynamics of a thin...Working with Professor T. P. Witekski (Duke University, USA), we mathematically investigated the dynamics of a thin liquid film draining from the edge of a (constrained) domain.  Such problems frequently arise in industrial coating processes where domains are of finite extent.This work has now been published in EJAM (European Journal of Applied Mathematics):Pressure-dipole solutions of the thin-film equationM. BOWEN  and T. P. WITELSKI  European Journal of Applied Mathematicshttps://doi.org/10.1017/S095679251800013XPublished online: 02 April 2018

2014年度共同研究者：Burt Tilley

研究成果概要：An understanding of the dynamics of liquid jets is important in many applications such as in inkjet printing, for e...An understanding of the dynamics of liquid jets is important in many applications such as in inkjet printing, for example. Working with an international collaborator, we have been analytically and computationally investigating how externally applied temperature gradients can be used to better control (from the point-of-view of application to inkjet printers) both the printing speed and resolution.We have developed advanced computational methods that are capable of following the jet dynamics over many different length and time scales; we are also considering the application of parallelisation to the computations in order to improve the time taken for the simulations to run.The computations support additional analytical results, allowing us to understand, in particular, the approach to rupture of the jets (separation into droplets) and also how to control the initial instability of a uniform jet that leads to rupture.