Oscillating Residuals in Finer Mesh Case

Jake

I am able to get convergence for a coarse (non-conformal) mesh case but only after I drop the under-relaxation factor for momentum to 0.3. Thinking that this works, I made the mesh finer. But with this fine mesh case, the continuity and momentum equations residuals are oscillating and never quite converge. Interestingly, while the continuity and the momentum equations residuals are out of phase while oscillating.

Any advice will be appreciated.

Thank you.