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-   -   [snappyHexMesh] Delete cells with special volume (https://www.cfd-online.com/Forums/openfoam-meshing/172400-delete-cells-special-volume.html)

Tobi May 30, 2016 09:45

Delete cells with special volume
 
1 Attachment(s)
Hey together,

in the attachment you find a simple meshing example and I am trying to figure out how to remove these bad cells during the snap procedure. I know that I can move my backgroundmesh to get rid of these cells but I do not want to do it in this way. A look into the snappyHexMeshDict and the mesh quality controls is promising with 3 parameters:
Code:

//- Minimum pyramid volume. Is absolute volume of cell pyramid.
//  Set to a sensible fraction of the smallest cell volume expected.
//  Set to very negative number (e.g. -1E30) to disable.
minVol 1e-13;


//- Volume ratio of neighbouring cells (0 -> 1)
minVolRatio 0.01;



//- if >0 : preserve cells with all points on the surface if the
//  resulting volume after snapping (by approximation) is larger than
//  minVolCollapseRatio times old volume (i.e. not collapsed to flat cell).
//  If <0 : delete always.
//minVolCollapseRatio 0.1;

The first one is recognized by snappyHex mesh (I can see it in the output) but all bad cells remain. The last parameter (minvolCollapseRatio) is not working with negative or even values up to 0.9. And the parameter (minVolRatio) is also not working.

Hence, there are several questions:

  • Why we have these parameters if they do not influence the result
  • Does anybody know if minVolRatio or minVolCollapseRatio is working


Thanks in advance,
Tobi


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