|May 7, 2013, 04:59||
Mesh quality after snappyHex
Join Date: Mar 2013
Posts: 68Rep Power: 4
i'm running the case of a flow inside a rough channel. I'm trying to generate a proper mesh. The bottom roughness is formed by small cubical blocks.
Each block's surface mesh should be formed by approximately 4 cells in the vertical direction and 2 cells in the two horizontal directions (although the refined cells should be about 2.5 units wide, while the blocks are 4.5 units wide, so a BIT LESS than 2 cells).
After snappyHex, however, i ran checkMesh and the result is the following
Checking topology... Boundary definition OK. Cell to face addressing OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces ... Patch Faces Points Surface topology in 6410 6743 ok (non-closed singly connected) out 5600 5781 ok (non-closed singly connected) left 18367 19132 ok (non-closed singly connected) right 18367 19132 ok (non-closed singly connected) top 56000 56541 ok (non-closed singly connected) bottom 510205 595645 ok (non-closed singly connected) spires_patch0 46711 48691 ok (non-closed singly connected) roughness_patch0 603177 690348 ok (non-closed singly connected) hangar_patch0 38240 38481 ok (non-closed singly connected) Checking geometry... Overall domain bounding box (-10 -7 -0.00139171) (30 7 4) Mesh (non-empty, non-wedge) directions (1 1 1) Mesh (non-empty) directions (1 1 1) Boundary openness (3.74041e-16 1.31646e-15 -1.22914e-13) OK. Max cell openness = 4.21681e-16 OK. Max aspect ratio = 5.83191 OK. Minumum face area = 1.76458e-05. Maximum face area = 0.0200125. Face area magnitudes OK. Min volume = 6.93409e-07. Max volume = 0.00200123. Total volume = 2237.84. Cell volumes OK. Mesh non-orthogonality Max: 57.4584 average: 12.2611 Non-orthogonality check OK. ***Error in face pyramids: 7 faces are incorrectly oriented. <<Writing 7 faces with incorrect orientation to set wrongOrientedFaces ***Max skewness = 7.12497, 102 highly skew faces detected which may impair the quality of the results <<Writing 102 skew faces to set skewFaces Coupled point location match (average 0) OK.
I don't know if these informations are enough. If you need to know more i can post some screenshots or others dicts.
Thank you very much
|May 10, 2013, 05:39||
Join Date: Aug 2010
Posts: 74Rep Power: 7
Firstly check where these cells are located. Use foamToVTK -faceSet to write them in the vtk format and use paraview to view them. Then think of ways to refine those areas to get a better mesh.
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