Modeling thin liquid films: from liquid crystals to liquid metals

Understanding fluid instabilities on micro and nanoscale is relevant for a variety of reasons. From scientific point of view, modeling systems involving fluid-solid interfaces is challenging. From mathematical side, there are significant challenges involved in formulating well-defined models, particularly in the settings that are more complex than simple Newtonian films. Numerous applications of thin films provide further motivation for their studies, in particular regarding fluid film evolution and resulting instabilities whose understanding is crucial for making progress in the field of self- and directed- assembly on nanoscale.

This talk will focus on recently developed asymptotic models and computational techniques for thin films. The models to be considered include long-wave asymptotic approach as well as full Navier-Stokes based models. Both types of models have been augmented to explicitly include fluid/solid interaction forces via disjoining pressure approach. The simulation techniques include algorithms for GPU computing that allow for simulations of large domains and detailed analysis of various instability mechanisms within long-wave approach, as well as volume-of-fluid based simulations of Navier-Stokes equations. Two case studies will be discussed: (i) Liquid crystal films, for which the challenge is to include liquid-crystalline nature of the fluid in the model in a tractable manner, and (ii) Liquid metal films irradiated by laser pulses; in this case, one of the challenges is to include complex thermal effects into consideration and understand their influence on the film instability and resulting pattern formation.

Particular issues that will be considered include the influence of the initial geometry on the instability development, Marangoni effects, and the instabilities in the case of multi-fluid configurations.