how to remove or join bad/tiny cells
 

Hi everybody,

from time to time I have severe problems with meshes that contain bad shaped or very small cells in areas with high fluid velocities or gradients. The cells usually result from the refinement and snapping process of snappyHexMesh or cartesianMesh (cfMesh). Due to these bad cells the simulations either run extremely slow (Courant adaption) or even crash (numeric problems).

Please let me know if you know a tool that allows to join small/bad cells with neighboring cells in order to weaken the CFL conditions or improve the mesh quality!

I already know I can remove some of the bad cells by using checkMesh and setSet (see https://openfoamwiki.net/index.php/SetSet). I also know that it's much better to obtain a better mesh in the first place, but that's not possible for some really complicated geometries.

Thanks!
Cutter

I'm also interested in this. You can use the Co utility to generate a field containing the CFL values, and then filter it with topoSet I think. But I don't know how to go on from there. How to join specific cells with neighbours?