Numerical Simulation of the Hydrodynamics of Thin Films & Droplets

Many natural and technological processes involve phenomena dominated by interfacial mechanics, that is, occurring within the regions of intersection between several fluid and/or solid phases. Applications range from coatings and films to foams. In particular, coatings, manufactured by the deposition of a liquid film on a solid substrate, are of significant industrial importance, and they are used in a large number of products.

In addition to capillary and gravitational effects, interfacial phenomena typically involve the interplay of complex processes such as dynamic contact lines, surface active materials, adhesion, temperature and/or compositional gradients, evaporation, etc. The exact mechanics governing such processes, such as the hydrodynamics controlling wetting, or the macroscopic action of surfactants in the evolution of films or coatings, is still not fully understood.

Our research brings together the fields of fluid mechanics, capillary mechanics, colloid and interface science, rheology, as well as transport theory. Our goal is to improve the understanding of the fundamentals of interfacial phenomena by using a combination of mathematical modeling, continuum theories and advanced computational techniques. Elucidating the physical mechanisms underlying complex interfacial phenomena will translate into improved, optimized and controlled interfacial processing.

The goal of this project is to develop numerical methods for interfacial flows, such as that governing droplets or liquid films, by using an Eulerian-Lagrangian approach. Our interest is not simply in creeping flows, but also in interfacial phenomena driven by high-speed air flow, including contact line motion on hydrophilic and hydrophobic surfaces, as well as by thermally induced effects. The Eulerian-Lagrangian approach is used for its ability to treat two-phase flows by accurately tracking the gas-liquid interface. This scheme has been applied to predict the spreading of capillary-driven and injection-induced droplets. It has been found to be in agreement with experiments.

Examples of two-phase flows and related interfacial phenomena can be found in energy conversion systems, heat exchangers, environmental control, and in pharmacological, biological, or oil recovery systems.

Simulation of Droplet Spreading Dynamics by Particle Finite Element Method, E. Mahrous, R.V. Roy, A. Jaurata & M. Secanell, 72nd APS Fluids Dynamics Meeting}, Seattle, November 23-26, 2019.

A Moving Mesh Finite Element Model for Droplet Spreading Analysis, E. Mahrous, A. Jarauta, T. Chan, P. Ryzhakov, A. Weber, R.V. Roy, and M. Secanell, submitted to Physics of Fluids.