How to use compressible gas flow .

Hi

I am trying to find a module for doing the analysis of a gas flow in a little 2-d chamber where I am using a compressible gas at a predefined pressure from a tank ranging from 3-6 psi-g at the inlet and the a shower-head like outlet . I want to see the effect of gas pressure or may be the velocity of jets from the outlet on a solid object lying on top of it.

Thanks in advance everybody.