Dear community,

I am interested in modeling capillary forces in porous media using the VOF model. The reason for using VOF is mere because of stability. Eulerian-Eulerian is too sensible to IC and most of the case it just diverges or blows up.

I have reviewed the literature and I found two interesting papers, that shed some light on how to determine the capillarity pressure and force in a porous media based on the porosity and permeability. Interested readers refer to:

1.- Article A general formula for capillary suction-pressure in porous media

2.- Article CAPILLARY PRESSURE IN POROUS MEDIA

These two works made great work defining such parameters. However, when we are modeling extra terms in VOF, we need to include those as a volumetric source term (body force) at least in STARCCM+.

My question is how to cast that force that represents the net force on the pad when a "radius of equivalent capillary " is used to represent the porous media.

So far, I've failed at casting that term into a body force source term. One thing that needs to be check is that the sum of the gravity force (another body force) + the net capillary force must be positive. In my case, I still have a negative number, meaning that my capillarity force is not big enough to overcome gravity.

Any suggestion ??

Julio