Numerical Simulation of Droplet Impact on Wettability-Patterned Surfaces

The analysis of droplet impact on micro-structured surfaces is a very challenging problem since it involves several physical phenomena interacting with one each other at levels of correlation depending on space and time. Moreover, understanding the dynamics and the main parameters a ecting the droplet behavior can give the capability to control and take advantage of its potential in di erent practical applications. In this work, rstly a phenomenological investigation of the phenomenon is provided involving models present in the literature and proposed theoretical analyses. Some fundamentals regarding numerical methods used in Computational Fluids Dynamics are presented in order to give the basis for the simulation set-up: particular attention is given to the contact angle boundary condition. Successively, several case studies are run with the open source software OpenFOAM: impacts on both surfaces with uniform and heterogeneous wettability characteristics are numerically simulated, with particular attention to cases exhibiting "morphing" and "vectoring" outcomes.