Let's talk about foamyHexMesh
 

I just wanted to hear if anyone has been successfully using the new mesher? There hasn't been much buzz around it since the release of 2.3.0 and it's already October.

The biggest issue I'm having is the mesh quality after collapseFaces. It just isn't usable and even the tutorial meshes are bad. I mean for example the flange tutorial, compare the output of fresh tutorial run (image attached) with the image on the page http://www.openfoam.org/version2.3.0/foamyHexMesh.php. I don't think they quite match.

I'd like to hear about your experiences with foamyHexMesh and maybe get an "official" opinion about the issues.

What is the actual mesh quality like from checkMesh?

Those look like it could be a polygon visualisation issue with paraview. If you instead view the patches those artefacts will disappear.

It's not just an visualization issue. I calculated simple pipe flow with foamyHexMesh generated mesh and there were pressure anomalies along with the "gaps" in the mesh. I've also tried all visualization options paraview has to offer and the holes won't go away. You can check this by zooming inside the mesh or using cutting planes.

You'll have to provide a full test case, and please post the output of checkMesh when complaining about meshes.

Ok I need to back down from my latest claim. It doesn't seem to affect the CFD results as I ran it again now. I could swear it did after 2.3.0, but that's probably my error. Mesh can be generated with ./Allrun.

Anyway, here is the test case and checkMesh results for a simple pipe mesh. There are initial condition files in the directory 0.org for running the pipe case with simpleFoam.

https://dl.dropboxusercontent.com/u/...amytest.tar.gz

Now, if the meshing is actually working, how can the mesh be refined only in the wall-normal direction?

For pipes you could try foamyQuadMesh. You would just mesh a circle and then extrude it however you want.

If you look at one of the tutorials as a starting point:

https://github.com/OpenFOAM/OpenFOAM...llShapeControl

One thing you can do depending on how the surface of your pipe is defined is specify the cell size settings for the pipe (with appropriate values):

pipeSurface
{
type searchableSurfaceControl;
priority 1;
mode inside;
forceInitialPointInsertion on;

surfaceCellSizeFunction uniformValue;
uniformValueCoeffs
{
surfaceCellSizeCoeff 1;
}

cellSizeFunction linearDistance;
linearDistanceCoeffs
{
distanceCellSizeCoeff 1;
distanceCoeff 4;
}
}

To get only wall normal refinement the ends of your pipe will need to be in a separate surface to the cylindrical wall.

Wouldn't this refine the cells in all directions like in my example? What I'm looking for is refinement of the cells only in the wall normal direction, in the spirit of refineWallLayer or boundary layer addition in snappyHexMesh. Would this be possible using foamyHexMesh?

I just played with this foamHexMesh for fun. And this is a pic from the tutorial of flange: I think its okay, dont forget show the mesh on time step 102.

I didnot change anything, did u change your dict? and did you run collapseEdges? this will filter out the small faces.
I saw many small faces in your latest pic.

Attachment 74079

Attachment 74080

Attachment 74081



I have the same problem on all tutorials in version 1906, 1712 and 7.0.
The tutorial straightDuctImplicit has the best behavior, here there are no holes in the mesh but some internal walls in the duct, that appears in the final step collapseEdges -collapseFaces


I can't upload the full case due to size (it is the unmodified tutorial files), but I have attached a screenshot and the last two log files after the problem appears.


Can it be regional settings on my computer or a wrong version of a library?


Best regards,


Per