(254f) Numerical Investigation of a Water Droplet on Vibrating Surface with and without Inclination

Modeling of droplet-surface interaction remains a challenge in fluids research, because of its complex, multiscale nature that involves both microscale interactions and macroscale flows. To understand its underlying mechanisms is important for the application design. The interactions amongst liquid/gas/solid molecules dominate the contact line dynamics, and determines the stationary and dynamic contact angles. The interactions between liquid/solid molecules also governs friction on the surface. We propose a novel numerical method to handle the droplet on a superhydrophobic surface, and validate our model with experiments on a 3mm water droplet sitting on a vibrating surface. A variable surface tension field is used to model the superhydrophobic behavior, and a term based on the gradient of surface tension is formulated to compensate the surface tension force. Different cases have be investigated for validating our methods and understanding of the underlying physics. Although the vibration-induced wetting transition was investigated in some recent studies, the vibration mechanism of droplet shedding has not yet been fully understood. This research quantitatively considers the effect of vibration on droplet shedding under various vibration resonance conditions, providing a possible way to effectively shed droplet off surfaces in condensation applications.