Surface snapping problem in snappyHexMesh
I've experienced a peculiar snapping problem when meshing a 2D airfoil profile with SHM v1606+.
The attached pictures show the surface mesh, on which some vertices have been distorted for no reason apparent to me. The detected features edges are far away (shown in white) and the underlying STL has no irregularities.
After the castellation stage, the mesh looks good - no irregularities in this region - checking the mesh at each stage confirm the problem occurs during the snapping phase, not castellation or layer addition.
In the problematic run, explicit feature edge capturing was set to on, implicit off. Switching all feature edge snapping off, the problem no longer occurs. Using implicit feature capturing, the problem also does not occur.
I tried changing the number of parallel processes and the problem went away again.
So this would seem to indicate that the problem is related to explicit feature edge snapping and is sensitive to the domain decomposition.
I hope this helps to localise the problem. I have a workaround (change number of parallel processes), so the urgency for this particular case is now relaxed.
Thanks and best regards,