I have 6 filters side by side in parallel ( filter is of hollow rectangular shape with 5 mm thickness) in a chamber. flow enters with the inlet velocity of 50 m/sec  through a pipe of diameter 60 mm and hits the diverge plate to distribute throughout the chamber. The task is gas has to enter through the porous media from all sides and should rise and escape from the top as the plate with the rectangular cuttings seperates the clean and dirty gas side . when I do the simulation the results are bit strange. The gas is entering only through certain filters porous medium and not from all the filters.