renumberMesh cause severely non-orthogonal faces

popstar0426 · February 14, 2017, 09:40

Deal all:

I used pointwise 18.0 to generated a structured mesh for an airfoil.
Before the renumberMesh step, checkMesh shows everything OK.

Checking geometry...
Overall domain bounding box (-19.5 -20 0) (40 20 0.01)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (-1.56059e-20 1.84567e-20 -1.24096e-14) OK.
Max cell openness = 1.70443e-14 OK.
Max aspect ratio = 769.513 OK.
Minimum face area = 9.93236e-09. Maximum face area = 2.29846. Face area magnitudes OK.
Min volume = 4.96618e-11. Max volume = 0.0114923. Total volume = 22.0781. Cell volumes OK.
Mesh non-orthogonality Max: 17.9459 average: 7.75933
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.461725 OK.
Coupled point location match (average 0) OK

Once the mesh was renumberMeshed, the severely non-orthogonal appeared.
Checking geometry...
Overall domain bounding box (-19.5 -20 0) (40 20 0.01)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (-4.05965e-20 -9.81742e-21 -6.8402e-15) OK.
Max cell openness = 1.8775e-14 OK.
Max aspect ratio = 769.5 OK.
Minimum face area = 9.93262e-09. Maximum face area = 2.29842. Face area magnitudes OK.
Min volume = 4.96631e-11. Max volume = 0.0114921. Total volume = 22.0781. Cell volumes OK.
Mesh non-orthogonality Max: 86.2438 average: 8.62636
*Number of severely non-orthogonal (> 70 degrees) faces: 700.
Non-orthogonality check OK.
<<Writing 700 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 0.46166 OK.
Coupled point location match (average 0) OK.

How to solve this problem?

Best regards!
Michael

alexeym · February 14, 2017, 10:57

Hi,

What is your writeFormat and writePrecision?

popstar0426 · February 16, 2017, 11:41

Quote:

Originally Posted by alexeym

Hi,

What is your writeFormat and writePrecision?

Dear Alexey:

Do you mean the "writeFormat" and "writePrecision" of pointwise to polyMesh?
I used pointwise to generate a 2d airfoil mesh, and extrude it to 3d with 2 cells in the spanwise direction. Then I set the BCs. Export "CAE" to a polyMesh (openfoam mesh) which can be copied directly to the constant folder.

Or do you mean there is "writeFormat" and "writePrecision" of renumberMesh?

Best regards!

alexeym · February 16, 2017, 11:57

Hi,

I mean writeFormat and writePrecision, which are in your system/controlDict. By default in tutorials it they are usually "ascii" and 6. And if you have mesh with small elements precision 6 is not enough (and this is usual reason for this non-orthogonality issues after renumberMesh - https://bugs.openfoam.org/view.php?id=2228).

popstar0426 · February 17, 2017, 00:09

Quote:

Originally Posted by alexeym

Hi,

I mean writeFormat and writePrecision, which are in your system/controlDict. By default in tutorials it they are usually "ascii" and 6. And if you have mesh with small elements precision 6 is not enough (and this is usual reason for this non-orthogonality issues after renumberMesh - https://bugs.openfoam.org/view.php?id=2228).

Dear Alexey:

Thank you very much.
The problem has been solved.

Best regards!

PRATBHARAT · August 6, 2019, 05:40

Overall domain bounding box (-0.00403 -0.00103 0) (0.00403 0.00103 0.00104)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (8.532656034e-18 -1.332719609e-16 5.504011285e-16) OK.
Max cell openness = 2.2465669e-16 OK.
Max aspect ratio = 14.18900306 OK.
Minimum face area = 5.754273324e-10. Maximum face area = 3.011071157e-08. Face area magnitudes OK.
Min volume = 1.313195917e-14. Max volume = 1.603538315e-12. Total volume = 1.726778556e-08. Cell volumes OK.
Mesh non-orthogonality Max: 75.30929246 average: 17.45011295
*Number of severely non-orthogonal (> 70 degrees) faces: 34.
Non-orthogonality check OK.
<<Writing 34 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 0.7423785989 OK.
Coupled point location match (average 0) OK.

I am getting the issue of non orthogonality. I am using ansys workbench for meshing. Can you help me to resolve this issue?
Thanks in advance ..

February 14, 2017, 09:40	renumberMesh cause severely non-orthogonal faces	#1
popstar0426 New Member Yue Wang Join Date: Sep 2009 Posts: 14 Rep Power: 16	Deal all: I used pointwise 18.0 to generated a structured mesh for an airfoil. Before the renumberMesh step, checkMesh shows everything OK. Checking geometry... Overall domain bounding box (-19.5 -20 0) (40 20 0.01) Mesh has 3 geometric (non-empty/wedge) directions (1 1 1) Mesh has 3 solution (non-empty) directions (1 1 1) Boundary openness (-1.56059e-20 1.84567e-20 -1.24096e-14) OK. Max cell openness = 1.70443e-14 OK. Max aspect ratio = 769.513 OK. Minimum face area = 9.93236e-09. Maximum face area = 2.29846. Face area magnitudes OK. Min volume = 4.96618e-11. Max volume = 0.0114923. Total volume = 22.0781. Cell volumes OK. Mesh non-orthogonality Max: 17.9459 average: 7.75933 Non-orthogonality check OK. Face pyramids OK. Max skewness = 0.461725 OK. Coupled point location match (average 0) OK Once the mesh was renumberMeshed, the severely non-orthogonal appeared. Checking geometry... Overall domain bounding box (-19.5 -20 0) (40 20 0.01) Mesh has 3 geometric (non-empty/wedge) directions (1 1 1) Mesh has 3 solution (non-empty) directions (1 1 1) Boundary openness (-4.05965e-20 -9.81742e-21 -6.8402e-15) OK. Max cell openness = 1.8775e-14 OK. Max aspect ratio = 769.5 OK. Minimum face area = 9.93262e-09. Maximum face area = 2.29842. Face area magnitudes OK. Min volume = 4.96631e-11. Max volume = 0.0114921. Total volume = 22.0781. Cell volumes OK. Mesh non-orthogonality Max: 86.2438 average: 8.62636 *Number of severely non-orthogonal (> 70 degrees) faces: 700. Non-orthogonality check OK. <<Writing 700 non-orthogonal faces to set nonOrthoFaces Face pyramids OK. Max skewness = 0.46166 OK. Coupled point location match (average 0) OK. How to solve this problem? Best regards! Michael

February 16, 2017, 11:57		#4
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, I mean writeFormat and writePrecision, which are in your system/controlDict. By default in tutorials it they are usually "ascii" and 6. And if you have mesh with small elements precision 6 is not enough (and this is usual reason for this non-orthogonality issues after renumberMesh - https://bugs.openfoam.org/view.php?id=2228). randolph and Ramzy1990 like this.

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February 14, 2017, 10:57		#2
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, What is your writeFormat and writePrecision?

August 6, 2019, 05:40		#6
PRATBHARAT New Member Pratyush Kumar Join Date: Jun 2019 Location: Mumbai Posts: 19 Rep Power: 6	Overall domain bounding box (-0.00403 -0.00103 0) (0.00403 0.00103 0.00104) Mesh has 3 geometric (non-empty/wedge) directions (1 1 1) Mesh has 3 solution (non-empty) directions (1 1 1) Boundary openness (8.532656034e-18 -1.332719609e-16 5.504011285e-16) OK. Max cell openness = 2.2465669e-16 OK. Max aspect ratio = 14.18900306 OK. Minimum face area = 5.754273324e-10. Maximum face area = 3.011071157e-08. Face area magnitudes OK. Min volume = 1.313195917e-14. Max volume = 1.603538315e-12. Total volume = 1.726778556e-08. Cell volumes OK. Mesh non-orthogonality Max: 75.30929246 average: 17.45011295 *Number of severely non-orthogonal (> 70 degrees) faces: 34. Non-orthogonality check OK. <<Writing 34 non-orthogonal faces to set nonOrthoFaces Face pyramids OK. Max skewness = 0.7423785989 OK. Coupled point location match (average 0) OK. I am getting the issue of non orthogonality. I am using ansys workbench for meshing. Can you help me to resolve this issue? Thanks in advance ..