I did it like you recommended (picture here of my simple 3D case). However I face the problem, when I set for the porous jump conditions a thickness of 1mm the calculation diverges. When I use a thickness of 0,01mm the solution converges. C2 is in my case 0. Face permeability (= permeability I used in standard porous zone in my other setup) = 1e-11. Do you have any idea why the solver has a problem with the thickness lager then 0,01mm? my case is super simple here and for more complex 3D case I face the same problem. I dont think it is related to the mesh. nFor my 3D case I also receive these two errors when usin 1mm thickness (maybe they help). I could not really find something online that was helpfull.detecting divergent flow at 1D porous jump zone 3nReverse porous jump zone 3 orientation based on bulk flow directionnbest regards, Alexn