How to define the porous baffle
 

I tried to use the Star-CD to calculate the porous media flow. Now, I had the pressure drop of filter by Experiment. delta_P=40*velocity. I try to define the alapa and beta alapa=0 beta=40/density

I find the result the pressure drop is different to experiment. Could anybody tell me how to define the alapa and beta? Thanks.

Aga