Numerical analyses of the coupled-dynamic behavior of droplets on a vibrating membrane with a microsphere array at a three-phase interface

Abstract

Analyses of the dynamic behavior of droplets are significant for a broad range of industrial applications. However, previous works have primarily studied the dynamic behavior on solid flat plates. Therefore, they could consider both the effect of geometric structure and energy simultaneously. In order to analyze the coupled-dynamic behavior of droplets, SMA membranes with microsphere arrays were used to apply the effects of both geometry and energy to droplet surfaces. The shape of the droplet changed harmonically with time during actuation. In the simulation, 50 and 200 Hz excitations related to the first and second droplet frequencies, respectively were used in order to investigate the coupled-behavior of the droplet. COMSOL Multiphasics (TM) was used to numerically analyze the dynamic behavior of droplets. The simulation results showed that the dynamic behavior of the water droplet was strongly affected by the natural frequency, and the interface and behavior were determined by both the mode shape and vibrating energy. As the actuation frequency increased, the energy equilibrium changed at the interface and occasionally broke. And then, the contact line on the actuated surface was changed to create new stable state.