A penalization technique applied to the “Volume-Of-Fluid” method: Wettability condition on immersed boundaries

• A penalization approach is applied to the “Volume-Of-Fluid” method.
• We focus the study on the wetting effect enforced on the surface of immersed objects.
• A spatial shift between boundary conditions is proposed to keep the method stable.
• The method is validated on several cases of capillary-dominated flows.

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 capillary-dominated flows, which represent the most challenging cases for VOF simulations.