I have a problem with non-equilibrium porous medium in 2d simulation. I am simulation a channel, only one section of the channel at the middle is porous medium, the remaining parts of free-stream channel. When I select non-equilibrium, the solid mesh is generated and the problem is that two solid walls are generated at the borders of porous zone and normal challen zone. As a result, the channel is blocked! there is no way to change those walls to interior boundary! please help me how can I solve that. I should note that in 3D simulation it doesn't happen, but 2D.