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[snappyHexMesh] snappyHexMesh refinement issue |
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October 9, 2019, 12:24 |
snappyHexMesh refinement issue
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#1 |
New Member
Najmiddin
Join Date: Dec 2018
Posts: 16
Rep Power: 7 |
Hi everyone, I am using SHM to mesh an stl file I generated. After running snappy I dont get the meshing I expected.
As you see in the picture below some cells are coarser than the others. I want all of it to be same mesh.jpg My snappyHexMeshDict is as below: Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 4.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; object snappyHexMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // // Which of the steps to run castellatedMesh true; snap true; addLayers false; geometry { baffle03.stl { type triSurfaceMesh; name baffle; } }; castellatedMeshControls { maxLocalCells 300000; maxGlobalCells 5000000; minRefinementCells 0; maxLoadUnbalance 0.10; nCellsBetweenLevels 2; features ( { file "baffle03.eMesh"; level 5; } ); refinementSurfaces { baffle { level (5 5); patchInfo { type wall; } } } resolveFeatureAngle 30; refinementRegions { } locationInMesh (0.001 -0.001 0.001); allowFreeStandingZoneFaces true; } snapControls { nSmoothPatch 3; tolerance 2.0; nSolveIter 300; nRelaxIter 5; nFeatureSnapIter 10; implicitFeatureSnap true; explicitFeatureSnap false; multiRegionFeatureSnap false; } addLayersControls { relativeSizes true; layers { } expansionRatio 1.0; finalLayerThickness 0.5; minThickness 0.2; nGrow 0; featureAngle 30; slipFeatureAngle 30; nRelaxIter 5; nSmoothSurfaceNormals 1; nSmoothNormals 3; nSmoothThickness 10; maxFaceThicknessRatio 0.5; maxThicknessToMedialRatio 0.3; minMedianAxisAngle 90; nBufferCellsNoExtrude 0; nLayerIter 50; } meshQualityControls { maxNonOrtho 65; maxBoundarySkewness 20; maxInternalSkewness 4; maxConcave 80; minFlatness 0.5; minVol 1e-13; minTetQuality 1e-30; minArea -1; minTwist 0.02; minDeterminant 0.001; minFaceWeight 0.02; minVolRatio 0.01; minTriangleTwist -1; nSmoothScale 4; errorReduction 0.75; } writeFlags ( layerSets ); mergeTolerance 1e-6; // ************************************************************************* // Last edited by najimaddin96; October 9, 2019 at 12:25. Reason: tags forgotten |
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October 15, 2019, 00:16 |
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#2 |
New Member
raphael
Join Date: Dec 2015
Posts: 5
Rep Power: 10 |
Hello,
Can you send the checkMesh result? and the snappyHexMesh log files? It may be due to maxGlobalCells or maxLocalCells |
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October 15, 2019, 04:58 |
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#3 |
Member
Damian Berghof
Join Date: May 2019
Posts: 41
Rep Power: 10 |
The refinement and quality of the mesh and required wall resolution are strongly related to your simulation task and chosen model. Which physical problem do you want to simulate?
best, Damian
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October 15, 2019, 09:51 |
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#4 |
Member
Thomas Sprich
Join Date: Mar 2015
Posts: 76
Rep Power: 10 |
Hi,
To refine the entire region add: Code:
baffle { mode inside; levels ((1E15 5)); } to refinementRegions assuming you haven't hit the maxGlobalCells and maxLocalCells limits mentioned by rapoutin. Thomas |
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November 9, 2019, 13:34 |
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#5 |
New Member
Najmiddin
Join Date: Dec 2018
Posts: 16
Rep Power: 7 |
Hi everyone, thanks so much for the replies and sorry for the late reply. @rapoufin, @virengos, @swift, I solved my problem by increasing nCellsbetweenLevels value to 9. The mesh got better, but my geometry had ~30million cells. For the same base mesh, I tried a different design, and surprisingly even with low nCellsbetweenLevels value, I get better mesh with less number of cells. Swift thank you for your recommendation, I will try it as soon as I will have to try new mesh. And by the way I @virengos, I am analyzing water flow inside a contact tank and use simpleFoam.
Best, Nazhmiddin |
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