Fluid-Structure interaction
 

I am modeling fluid-structure interaction. I want to know the pressure distribution inside a 3-D rectangular channel in following two cases. Without giving deflection to the top surface and by applying deflection function to the top surface.
Inputs are velocity(u,v & w) at the inlet, pressure at the outlet and no-slip conditions at the walls.
Ideally, how should be the pressure distribution on the top surface without any deflection?
Which software is recommended for this type of problem?
Any help would be appreciated.

Thanks
Pranav