Modeling internal using porous media model - flow get stuck under the object
 

Hi!

I'm relatively new in CFD. I'm trying to model the multiphase flow through thin (5mm) porous internal using porous media model. The simulation converges nicely, but then suddenly crashes. Looking on the gas volume fraction contour I can see that in some regions the fluid flows freely, but in another, gas get stuck under the object and there is no flow through it. This creates kind of "dead zone" after the object. I think that causes deconvergence, but I don't know how to solve this problem. I couldn't find any similar issues anywhere.

I tried different meshing strategies including local sizing in porous zone region. The time step is small (0.001). The mesh there is very fine (max.1 mm cell length) The quality of mesh is good. The model is as simple as possible.

Does anyone has an idea what can cause such issue? I truly appreciate any ideas.