turbulent viscosity causes solution divergence

Steve

Running a simulation where a square duct intersects a circular volume, there are narrow triangular sections which it seems impossible to eliminate elongated cells from.

The turbulent viscosity becomes very high in this region and causes the solution to diverge, particularly continuity.

What is a good solution to this grid/solution problem? Adding more elements I understand may risk negative volume connectivity issues. Any other suggestions?

Thanks, Steve