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February 9, 2016, 08:59 |
mesh quality requirement
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#1 |
New Member
stefano zinna
Join Date: Mar 2009
Posts: 29
Rep Power: 17 |
Hi All,
Do you know if there is a general guidlines for quality reuirement in openfoam. Something like: mesh should have orthogonality less than..., aspect ratio less than ... etc.. I know that it is case dependent but i am looking for a "first guess" guidlines. regards, Stefano |
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February 9, 2016, 10:34 |
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#2 |
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gereksiz
Join Date: Mar 2015
Posts: 42
Rep Power: 11 |
I also wonder how accurate the checkMesh of OF.
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March 19, 2016, 15:43 |
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#3 |
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Vinícius da Costa Ávila
Join Date: Jul 2015
Location: Porto Alegre, Brazil
Posts: 62
Rep Power: 10 |
Hi, I am no expert, but as you said, it depends HIGHLY on the solvers you use.
Also, OF has a standard limiting values for mesh quality with checkMesh (these standard values are mostly for reference, since they can be changed by the user). Standar values used in OF ($WM_PROJECT_DIR/src/OpenFOAM/meshes/primitiveMesh/ primitiveMeshCheck/primitiveMeshCheck.C) • Foam::scalar Foam:rimitiveMesh::closedThreshold_ = 1.0e-6; • Foam::scalar Foam:rimitiveMesh::aspectThreshold_ = 1000; • Foam::scalar Foam:rimitiveMesh::nonOrthThreshold_ = 70; // deg • Foam::scalar Foam:rimitiveMesh::skewThreshold_ = 4; • Foam::scalar Foam:rimitiveMesh:lanarCosAngle_ = 1.0e-6; For example, for a case I'm used running: tutorial bubbleColumn with RAS turbulence models, I am able to run big meshes (more than a million cells) with the standard numerical solvers (fvSchemes and fvSolution) and Co=1.0 even with not very good meshes (but still within checkMesh quality limits) and I get accurate results. In my (brief) experience I would recommend as a start point: Aspect ratio: max 5-10 nonOrtho.: max 50-60 skewness: max 1-2.5 Then, I recommend mesh convergence studies to be made. So it will ensure your solution is mesh independent.
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