Finite Element Modeling of the Fluid Flow within Small Water Droplets in Contact with Rough Surfaces


Hydrophobic surfaces are water repellent surfaces. Water droplets, falling on such surfaces are repelled by the surface to form nearly spherical droplets, which for even minute surface inclinations, easily rolls off, sweeping away pollutant particles in the process and thus producing a cleaning effect. Such surfaces commonly exist in nature (e.g. lotus leaves) and can also be artificially constructed by generating specific surface topology. However, effective imitation of the phenomenon as occurring in nature demands a comprehensive understanding of the process based on a broad-based analysis. The project aims to develop this understanding using computational modeling and analysis tools. Three major objectives are pursued. Firstly, a finite element based fluid flow model is developed and implemented for internal flow behavior inside the droplet. In the second phase, the flow model is coupled with a contact formulation thus describing a model for a deformable droplet rolling on a rough surface. Finally, the resulting model is applied to the analysis of self-cleaning mechanism by performing a multiphase analysis comprising of three media i.e. water, surface and pollutant particle.