View Issue Details
ID | Project | Category | View Status | Date Submitted | Last Update |
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0001645 | OpenFOAM | Bug | public | 2015-04-02 17:05 | 2015-10-22 10:15 |
Reporter | Svensen | Assigned To | henry | ||
Priority | normal | Severity | major | Reproducibility | always |
Status | closed | Resolution | no change required | ||
Platform | GNU/Linux | OS | Ubuntu | OS Version | 14.04 |
Summary | 0001645: snappyHexMesh. irregular cells on snap stage | ||||
Description | Using snappyHexMesh some irregular cells were generated on snap stage (see picture). I've tried to modify meshQualityDict and irregular cell disappears after that. But the new incorrect cell appears in the next place... It seams like a bug.. (test case is attached. Select the coloring by cell. Irregular cells on surface have a maximum value of velocity) Test case: https://yadi.sk/d/CAGG4zC0fhm3q | ||||
Tags | No tags attached. | ||||
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My issue looks very similar to http://www.openfoam.org/mantisbt/view.php?id=1493, but it wasn't solved yet. Like it is written in this issue, the problems with Courant number occures in this cells, so it is impossible to get a solution in a reasonable amount of time. Can anyone fix this bug in snap stage ?? |
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snappyHexMesh creates the mesh you ask it to, obeying the mesh quality constraints. If you use put your mesh quality constraints in a system/meshQualityDict (see e.g. ./incompressible/simpleFoam/motorBike/system/meshQualityDict) you can run checkMesh -meshQuality and check the mesh against these constraints outside of snappyHexMesh. Other things to check - did you write the mesh in binary - what constraint gets rid of your problematic cells |
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First of all I've checked my stl surface and found some self-intersections. I repaired this and start the snappyHexMesh ones again. But suddenly I've got even worst result that it was before. There are some holes in the surface (look at the picture above). As you advised me, I've checked my mesh with checkMesh -meshQuality and it says OK. But if I run snappyHexMesh -checkGeometry I've got an error like: "Checking for triangle quality. flange : has 746 bad quality triangles (quality < 0.01)" So it looks very strange because surfaceCheck on stl surface doesn't show me any kind of error. If I simply run snappyHexMesh the mesh is created witout any type of error. Looks very strange... The test case is available here: https://yadi.sk/d/Q-8Xg8NsfxyvP |
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Hello, Im not an expert in this field. But I downloaded your case in the first link. Be default in paraFoam, U will find some holes in your mesh. You can neglect these holes. Also in this way it will look better: 1. select Use VTKpolyhedron 2. Do Not select the internal mesh, just select the patch. I do this for your case, I think its good. |
Date Modified | Username | Field | Change |
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2015-04-02 17:05 | Svensen | New Issue | |
2015-04-02 17:05 | Svensen | File Added: incorrect_cell.png | |
2015-04-03 09:54 | Svensen | Note Added: 0004558 | |
2015-04-10 15:12 |
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Note Added: 0004596 | |
2015-04-14 08:04 | Svensen | Note Added: 0004610 | |
2015-04-14 08:05 | Svensen | File Added: mesh_with_holes.png | |
2015-04-14 08:06 | Svensen | Note Edited: 0004610 | |
2015-04-30 09:19 | sharonyue | Note Added: 0004694 | |
2015-10-22 10:15 | henry | Status | new => closed |
2015-10-22 10:15 | henry | Assigned To | => henry |
2015-10-22 10:15 | henry | Resolution | open => no change required |