Desnity as a function of pressure
 

Hi,

I am simulating fluidised beds using Eulerian multiphase models and trying to solve it by having density as a function of pressure by a UDF. The solution this way diverges (continuity). When i give a constant density, it converges to a good solution. Please help me find out where I am going wrong. I have tried adjusting the URELs but there it still diverges.

Also what significance does speed of sound has on density of air?
Any help is highly appreciated.

Thanks,

Apurv