Numerical Simulation of Droplets Interacting with a Microcolumnar Solid Structure

Abstract

The VOF method is used to simulate the dynamics of a droplet interacting with a structure consisting of an array of microcolumns mounted on a flat surface. Such a specific configuration is intended to mimic the typical properties of lotus leaves, which typically display regularly arranged micron-scale papillary structures. After setting the initial velocity of the simulated droplet on the basis of practical considerations, an analysis is conducted about the effect of the characteristic size of the microstructure on the apparent contact angle. The pressure variation in the microstructure caves is also examined. The simulation results show that the change of the contact angle of the droplet in the quasi-static state is consistent with theoretical calculations and the contact angle in the dynamic state is smaller than that in the quasi-static state. Moreover, under dynamic conditions, the pressure fluctuation in the microstructure cave depends essentially on the characteristic size of the microstructure.