convergence
 

What should we do if 2 out of 10 CFD models do not converge? We need to compare CFD results amongst all 10 cases but 2 of them not converged. If we change under-relaxation factors for 2 of these, will our comparison be valid? What do people normally do when encounter this problem?

Re: convergence
 

Your final result should not depend on relaxation factor. For rectifying convergence problem, have look on the poorley formed / diverged solution, and try to find regions of unrealistic numerical values of physical parameters, for your case of application. That can give you an idea for reason of divergence.