[Eloise]

Hello,

I'm trying to stitch different meshes together. Here is what I found:
- internal mesh is a cylinder: no problem.
- internal mesh is a block: not possible (see here).
- internal mesh is a sphere: not possible (I did not succeeded).

Am I right? Or did one of you managed to stitch a block or a sphere inside another mesh?

Thanks for your feedback!
Eloïse

[wyldckat]

Greetings Eloïse,

I can only guess that it really depends on the meshes you've got to be stitched! Can you share simple case examples of what you're trying to do?

Best regards,
Bruno

[Eloise]

Hello Bruno,

Here are some test cases:
1) for a Cylinder: run .\Allrun_Cylinder. You can see that is works by looking at the log.checkMesh where the two internal patches have no faces.
2) for a Sphere: run .\Allrun_Sphere. The stitchMesh ends with an error.
3) for a Block: no test case, but I'd suggest to simply replace the sphere by a box in the Sphere test case.

Thanks for your interest in this case
Eloïse

[wyldckat]

Hi Eloïse,

These are awesome test cases !
But you forgot to mention that for the box and the sphere you were using snappyHexMesh!
And it's easily solved! The missing magic step if this after mergeMeshes:

rm 0/cc* 0/*Level

Those files are generated by snappyHexMesh for future reference, in case you want to do some advanced mesh manipulation and diagnosing.

In addition, you can use the "-overwrite" option in mergeMeshes as well (I'm using OpenFOAM 2.1.x and I haven't checked with 2.1.1):

#!/bin/sh
# Source tutorial run functions
. $WM_PROJECT_DIR/bin/tools/CleanFunctions
. $WM_PROJECT_DIR/bin/tools/RunFunctions
                          
cd IntDom_Sphere/
cleanCase
runApplication blockMesh  
runApplication snappyHexMesh -overwrite 

cd ../ExtDom_Sphere/
cleanCase
runApplication blockMesh 
runApplication snappyHexMesh -overwrite 
runApplication mergeMeshes -overwrite . ../IntDom_Sphere/  
rm 0/cc* 0/*Level
runApplication stitchMesh -partial -toleranceDict toleranceDict -overwrite sphere_ext_region0 sphere_int_region0

Best regards,
Bruno

[Eloise]

Hi Bruno,

Thanks for your fast answer! The sphere is indeed created with snappyHexMesh and this additional line solves it all . I haven't had time yet to work on the sphere creation in blockMesh, it will probably come soon.

It is already very good news that the stitching can work with spherical and cubic internal meshes when using snappyHexMesh!

I'm actually working with 2.0.x, so the -overwrite option is not available for mergeMeshes.

Regards,
Eloïse

[cutter]

Hi,

thanks for your test cases. I've tried them with OF 2.2.x, they're working without any problems.

Did you make any progress with the block case?! Occasionally I have similar problems that could only be resolved by preparing the whole mesh in an external tool. I therefore modified your Cylinder test case to create a Cube case by removing the arcs within the blockMesh files (see below). This causes stitchMesh to fail with the following error:

--> FOAM FATAL ERROR: 
Zero length edge detected.  Probable projection error: slave patch probably does not project onto master.  Please switch on enriched patch debug for more info

    From function void enrichedPatch::calcCutFaces() const
    in file slidingInterface/enrichedPatch/enrichedPatchCutFaces.C at line 263.

This is really strange since the two patches should match even perfectly. Can this be resolved by modifying the toleranceDict? Maybe it's even worth a bug report...

The same error has also been observed in StitchMesh on two patches and creating interface in openfoam.

Cutter