A penalization technique applied to the ''Volume-Of-Fluid'' method: wettability condition on immersed boundaries

A penalization approach is presented to simulate two-phase flow in the presence of immersed solid boundaries so as to consider highly complex objects such as porous media microstructures. Based on the standard Volume-Of-Fluid formulation, the method takes into account the wettability effects which may occur on the surface of immersed solid boundaries. A spatial shift between the no-slip and the wettability conditions is introduced to make the method stable, regardless of the simulation parameters. The penalized VOF model and the numerical choices are then validated by a series of tests on capillarydominated flows, which represent the most challenging cases for VOF simulations.