Simulation of droplet impact with dynamic contact angle boundary conditions
The numerical simulation of dynamic wetting processes is of interest for a vast variety of industrial processes, where practical experiments are costly and time-consuming. In these simulations, the dynamic contact angle is a key parameter, but the modeling of its behavior is poorly understood so far. In this article, we simulate droplet impact on a dry flat surface by using two different contact angle models. Both models show good qualitative and quantitative agreement with experimental results. For our numerical method, we solve the three-dimensional Navier-Stokes equations with finite differences on a staggered grid. The free surface is captured by a level-set method, and the contact angle determines the shape of the level-set function at the boundary. Additionally, we investigate the mass-conservation properties of two volume-correction methods, which are invaluable for the analysis of the droplet behavior.