I am simulating flow through a duct which has fluid coming in to the domain from the walls in addition to the main flow. Is defining a total mass source at the wall boundry represent the problem?

Is it equivalent to specifying a porous wall?

If no how can a porous wall boundary condition be set in CFX 10

If you know the distribution and the amount of flow that comes through the porous wall, I think that you could use a mass source at the wall. If you do not know it then you perhaps will need to include into your simulation a part of the domain outside the channel - then you could use a porous wall. I would specify a porous wall in this case as a thin 3d subdomain. This was for the case of no heat transfer through the wall. In case that you have heat transfer through the wall you would probably need to develop some UserCEL. I hope that this helps a bit. Ulian

Thanks a lot Ulian. I indeed do know the flow coming through the porous wall. I did specify it as a total mass source at wall. It works or atleast I think. Thanks for your response