[MarcusAng]

Hi all,

I am working on a porous media project where I would like to simulate a smaller volume from my initial STL with an upstream developing region, a simplified schematic is shown. As the project progresses, the STL file size would increase dramatically (1.5Tb) so I am avoiding cropping and repairing the geometry in a GUI.

Currently the way I am doing this is using snappyHexMesh where the initial blockMesh bounding box is smaller than the original STL. Then I create a separate blockMesh such that at the end of the block, the mesh size matches the minimum mesh size that snappyHexMesh can produce. Then I use mergeMesh to combine these cases together as suggested by a simple tutorial from https://openfoamwiki.net/index.php/S...vaned_diffuser. As recommended I use stitchMesh to get rid of the connecting patches and I delete the patches from the boundary file in constant folder.

This method works fine when running simpleFoam in serial however, when decomposing the mesh to run in parallel, I obtain the following error

Cell 432contains face labels out of range: 6(2341 2342 2343 2344 441136 -1) Max face index = 452878

A couple of troubleshooting points
1. Mesh looks fine before and after stitchMesh in ParaView and the connecting patch is not present.
2. decomposePar works for both mesh prior and after mergeMesh. It seems that the issue is with stitchMesh
3. I have tried stitchMesh -partial and changing the master and slave patch with no improvements.
4. The parallel simulation runs without deleting the patches in boundary file however, it is incorrect as the boundary condition is imposed when it shouldn’t

Any help on this would be appreciated and if there is a better way of cropping the STL and adding the developing region I would love to hear it. Please let me know if there are any files that may be helpful.

Thanks,
Marcus

Current Workflow after creating both individual mesh. OpenFOAM v2106 on a HPC cluster.

mergeMeshes porousMedia entrance -overwrite
stitchMesh -partial  maxX0 minX -overwrite
*edit boundary file*
decomposePar -force

The boundary file looks like this after stitchMesh

9
(
    minX
    {
        type            patch;
        nFaces          0;
        startFace       14126904;
    }
    maxX
    {
        type            patch;
        nFaces          6902;
        startFace       14126904;
    }
    minY
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          18039;
        startFace       14133806;
    }
    maxY
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          13381;
        startFace       14151845;
    }
    minZ
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          13933;
        startFace       14165226;
    }
    maxZ
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          12940;
        startFace       14179159;
    }
    PorousMedia
    {
        type            wall;
        inGroups        1(wall);
        nFaces          1651435;
        startFace       14192099;
    }
    minX0
    {
        type            patch;
        nFaces          576;
        startFace       15843534;
    }
    maxX0
    {
        type            patch;
        nFaces          111962;
        startFace       15844110;
    }
)

And looks like this after editing prior decomposePar

7
(
    maxX
    {
        type            patch;
        nFaces          6902;
        startFace       14126904;
    }
    minY
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          18039;
        startFace       14133806;
    }
    maxY
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          13381;
        startFace       14151845;
    }
    minZ
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          13933;
        startFace       14165226;
    }
    maxZ
    {
        type            symmetryPlane;
        inGroups        1(symmetryPlane);
        nFaces          12940;
        startFace       14179159;
    }
    PorousMedia
    {
        type            wall;
        inGroups        1(wall);
        nFaces          1651435;
        startFace       14192099;
    }
    minX0
    {
        type            patch;
        nFaces          576;
        startFace       15843534;
    }
)

[Alczem]

Hey!


I never used stitchMesh, but I can suggest an alternative.


You could try to create ACMI patches between the two meshes after merging them. There have been a couple of threads about this recently, I think it is worth a try