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Meshing thin cutouts with cfMesh

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Old   August 14, 2015, 05:09
Default Meshing thin cutouts with cfMesh
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Hi,

I try to mesh a fluid with a subtracted duct (see Picture 1) by using cfMesh.
But there is always the Problem, that cfMesh ignore my cutout (see Picture 2).
I used surfaceFeatureEdges to get sharp edges at the fluid and surfaceMeshRefinement with the duct as .stl to get a finer mesh in this Region.

Has someone an idea how I can get a good mesh?

Best regards,
Björn
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Old   August 20, 2015, 16:20
Default Remove cells near the cut-out
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Hi,

The cells near the cut-out are larger than the gap itself. Hence, pMesh does not resolve the gap because the initial mesh is designed to such that it is slightly larger that the domain that shall be meshed. This criterion results in the mesh being glued over the thin gap.
This problem can be solved either by refining the mesh such that the cells become smaller than the gap, or by using the removeCellsIntersectingPatches option for the patches at the cut-out. The second option will remove the cells intersecting the cut-out, and make the topology of the mesh similar to the geometry.
I hope this clarifies the cause of your problems.

Regards,

Franjo Juretic
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Old   January 14, 2016, 23:20
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Derwin Parkin
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hi Franjo,

Does removeCellsIntersectingPatches also help for dealing with baffles? Or is there another way to go about that?

I have a thin baffle surface in my geometry and I'm wondering what the best way to account for it in cfMesh is...
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Old   January 15, 2016, 05:20
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Hi,

removeCellsIntersectingPatches is an instruction for removing cells intersecting specified objects. In most cases, it is needed only when the cell size is larger than the features in a given region.
Baffles do not have a volume, and by using keepCellsIntersectingBoundary option, it is not possible resolve them irrespective of the selected cell size.
With baffles, the biggest problems are boundary edges, and the best way to overcome the problem is to extrude baffles into a volume, to avoid boundary edges.

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Franjo
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