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vishwa November 19, 2009 11:14

SnappyHexMesh errors..How to overcome these..
I had posted a couple days ago regarding the meshing of internal flow geometry say a pipe. When i run snappy, i can see that there is a large number of faces which are non-orthogonal and when run the checkMesh utility after it finishes, i get this at the end of the file

Checking geometry...
Overall domain bounding box (-0.003700000001 -0.007346000057 -0.0004600000102) (0.003700000001 0.001901651965 0.0004600000102)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (-1.21132342e-16 3.586989832e-14 1.385780927e-15) OK.
Max cell openness = 3.10768422e-16 OK.
Max aspect ratio = 20 OK.
***Zero or negative face area detected. Minimum area: 0
<<Writing 7 zero area faces to set zeroAreaFaces
Min volume = 1.931675752e-16. Max volume = 8e-14. Total volume = 1.673317339e-08. Cell volumes OK.
Mesh non-orthogonality Max: 148.2423307 average: 11.06677473
*Number of severely non-orthogonal faces: 78935.
***Number of non-orthogonality errors: 18.
<<Writing 78953 non-orthogonal faces to set nonOrthoFaces
***Error in face pyramids: 7 faces are incorrectly oriented.
<<Writing 7 faces with incorrect orientation to set wrongOrientedFaces
***Max skewness = 9.963874182, 980 highly skew faces detected which may impair the quality of the results
<<Writing 980 skew faces to set skewFaces

Failed 4 mesh checks.

the geometry is very simple.. It has a rectangular box and the end of the box is a half cylinder that is of the same height of the box and the radius of the cylinder is half the box width.

Any suggestions to overcome these errors?.


albcem November 21, 2009 06:59

You need to supply more information such as
  1. the snapphhexmesh dictionary file,
  2. the specifications of the underlying blockmesh (overall size, element sizes)
  3. Copy of the STL file for us to check whether there is anything wrong with it

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