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[snappyHexMesh] Mesh does not follow feature edges |
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August 12, 2022, 12:08 |
Mesh does not follow feature edges
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#1 | |
New Member
Schweiz
Join Date: Aug 2022
Posts: 8
Rep Power: 3 |
Hi all,
I'm relatively new to OpenFOAM, so unfortunately I feel completely lost with the following problem and have no idea which knobs to turn: The case:
What you see in the screenshot:
The problem is that the pink feature edges do not follow the actual features of the building nicely. I suspect that Code:
snappyHexMesh |
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August 14, 2022, 01:47 |
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#2 |
Senior Member
Nejc
Join Date: Feb 2017
Location: Slovenia
Posts: 196
Rep Power: 9 |
It does seem that some more refinement could help. You have the following options:
- make a finer background mesh by changing the number of cells in blockMeshDict - volume refinement (the 'box' you're talking about) - Refine cells on buildings' surfaces - Refine cells on edges. Those options are sorted by number of additional cells they will generate. I'd recommend the 'surfaces' option, just add refinementSurfaces to castellatedMeshControls, then increase level step by step. https://www.openfoam.comu/documentat...nementSurfaces If you share your snappy dict, I can show you more precisely. |
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August 15, 2022, 08:53 |
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#3 |
New Member
Schweiz
Join Date: Aug 2022
Posts: 8
Rep Power: 3 |
Thanks a lot for the help! I inserted the snappy dict below. It's directly taken from the
Code:
windAroundBuildings Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: v2112 | | \\ / A nd | Website: www.openfoam.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; object snappyHexMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // #includeEtc "caseDicts/mesh/generation/snappyHexMeshDict.cfg" castellatedMesh on; snap on; addLayers off; geometry { buildings.obj { type triSurfaceMesh; name buildings; } refinementBox { type box; min (-97.1975 -110.911 0.0); max (137.1975 150.911 78.0); } } castellatedMeshControls { features ( { file "buildings.eMesh"; level 1; } ); refinementSurfaces { buildings { level (3 3); patchInfo { type wall; } } } refinementRegions { refinementBox { mode inside; levels ((1E15 2)); } } locationInMesh (1 1 1); } snapControls { explicitFeatureSnap true; implicitFeatureSnap false; } addLayersControls { layers { "CAD.*" { nSurfaceLayers 2; } } relativeSizes true; expansionRatio 1.2; finalLayerThickness 0.5; minThickness 1e-3; } meshQualityControls {} writeFlags ( noRefinement // scalarLevels // layerSets // layerFields ); mergeTolerance 1e-6; // ************************************************************************* // |
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August 15, 2022, 14:42 |
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#4 |
Senior Member
Nejc
Join Date: Feb 2017
Location: Slovenia
Posts: 196
Rep Power: 9 |
Code:
features ( { file "buildings.eMesh"; level 1; } ); refinementSurfaces { buildings { level (3 3); patchInfo { type wall; } } } |
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August 30, 2022, 07:52 |
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#5 |
New Member
Schweiz
Join Date: Aug 2022
Posts: 8
Rep Power: 3 |
Thanks, that helped and was also a good starting point to learn more about SnappyHexMesh.
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