Euler-Euler Model: reached singularity

I am running a Euler-Euler model and get a singularity error about six seconds into a 12 second analysis. It appears that there is a high velocity flair at an inlet when the singularity occurs. I have tried refining the mesh but the error returns. Any suggestions on how to relax convergence or to avoid this convergence issue? I am willing to accept some reduced accuracy in order to achieve convergence.