Solution doesn't converge if we set snap to True for a complex outdoor-airflow case

[ysun]

Hello,
I realize that, with a big and complex urbain case, the solution doesn’t converge if we set ‘snap’ to True for outdoor airflow, the calculation stop at T= 90.

Even though I refine mesh to a higer quality or et add more layers, it gave almost the same problem, the calculation stop at around 90 - 100.

But when I set snap to false, it works well. Can somebody explain ?

Thanks !

[kinonotofu]

Perhaps the continuity equation is diverging due to a highly-skewed mesh. Snapping to geometry tends to result in lower quality meshes.
It is a good idea to run Butterfly_chekMesh before running the calculation to check the quality of the mesh.