[Chouchou]

Hello, everyone,

Does anyone know how to deal with non-orthogonal and skew faces after checkMesh? Modify the model geometry to avoid it seems a tremendous amount of work.

Thanks in advance.

-Chouchou

[Ship Designer]

Hello Chouchou,

I've encountered the same problem in a case I'm working with, where checkMesh reports non-orthogonal and high-skew faces in the mesh. Since I'm attempting to validate the hull resistance of the DTC ship hull, albeit for a condition different than the one of the OpenFOAM tutorial, modifying the hull shape is out of the question.

A step-by-step approach to identify the source of the problem showed that the bad mesh elements get introduced in the layer adding step of snappyHexMesh. Before that, checkMesh reports mesh ok. I've tried to modify some of the settings in the addLayersControls dictionary but the errors persist.

Have you found a solution to your problem?

[Ship Designer]

According to this thread Visualize nonOrthoFaces set I was able to visualize the non-orthogonal faces, see attached pictures below. These faces are very far above the ship's hull and from the added boundary layer cells, at a transition between two refinement levels. When that region is looked at closer in profile view, it can be seen that the cells in that region are distorted and don't correspond to the original mesh grid anymore.

I have no explanation why snappyHexMesh distorts the mesh that far away from where the boundary layers are actually added. I also don't know what can be done to prevent this from happening and whether this is intended behaviour or some sort of bug. Any suggestion is appreciated, thanks.