mass convergance
 

I am doing the steady state analysis for comprissible flow I have a pboblem of mass convergance I am getting the convergance for all the residual except the mass residual which is fluctuating in between 0.1 to 0.01 continuosly between iteration 300 to 1200 while at 1000 iteration i got the convergance for all other residuals Can anybody help me to resolve this problem.

Regards

Kale

Re: mass convergance
 

Try to decrease the under-relaxation factors of pressure equation. sometimes it may be lower as 0.01 to get the convergenced solution.

Re: mass convergance
 

And if this doesn't help, It's possible that your geometry provokes an unsteady (oscillating) flow field in spite of the steady BC's. Is it by any chance a wide-angled diffuser....

Lars Ola