Turbulence Model Divergence After Mesh Refinement

Symptom: residuals explode after introducing localized refinement.

Likely causes

• Turbulence wall treatment mismatched to new y+ range.
• CFL cap too high for smaller cells.
• Inlet turbulence intensity not adjusted.

Tests to run

• Compute new y+ and switch to compatible wall functions.
• Lower the CFL limit and ramp back up.
• Refit inlet turbulence parameters to the refined mesh.