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Naruto September 27, 2013 12:40

Problem with rotating tools
 
2 Attachment(s)
Dear all,
My problem is quite strange in nature. I have been using pointwise v 16R3 for the last couple of months. Pointwise has released a new version "version 17". My lab has recently acquired the license of the newest release. Now comes the problem.

I am currently using a half cylindrical computational domain containing one single blade. After meshing this half cylinder, I rotate the whole computational domain and create a two bladed turbine. I am attaching a picture of the computational domain.

In pointwise I keep the solver Ansysfluent. I convert my mesh to a .cas file. Then I copy that .cas file to my linux machine and transfer it to OpenFOAM/polyMesh. Now here comes the problem. After converting the mesh into OpenFOAM I normally use checkMesh utility of OpenFOAM and the result is just crazy. I have been using the same procedure in pointwise v16 R3. It did not show any problem. :(
I am copying the error message below:
*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.1.0-bd7367f93311
Exec : checkMesh
Date : Sep 28 2013
Time : 01:22:31
Host : "hpc001"
PID : 19116
Case : /home/abdullah/Hope/inner
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
points: 329250
faces: 2326423
internal faces: 2296159
cells: 1058394
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 108040
prisms: 154360
wedges: 0
pyramids: 18566
tet wedges: 0
tetrahedra: 777428
polyhedra: 0

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
Rotor 3736 1968 ok (non-closed singly connected)
Rotor-AMI 5008 2602 ok (non-closed singly connected)
blade-2 21520 13806 ok (closed singly connected)

Checking geometry...
Overall domain bounding box (-0.7 -0.700014 -0.2) (0.7 0.700014 0.7)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (-5.97487e-18 9.05469e-17 -1.52007e-16) OK.
***High aspect ratio cells found, Max aspect ratio: 1.35622e+294, number of cells 36
<<Writing 36 cells with high aspect ratio to set highAspectRatioCells
Minumum face area = 4.81265e-14. Maximum face area = 0.00279988. Face area magnitudes OK.
Min volume = 1.66667e-300. Max volume = 4.86646e-05. Total volume = 1.3839. Cell volumes OK.
Mesh non-orthogonality Max: 111.714 average: 20.6478
*Number of severely non-orthogonal faces: 18175.
***Number of non-orthogonality errors: 432.
<<Writing 18607 non-orthogonal faces to set nonOrthoFaces
***Error in face pyramids: 191 faces are incorrectly oriented.
<<Writing 191 faces with incorrect orientation to set wrongOrientedFaces
***Max skewness = 11.0435, 94 highly skew faces detected which may impair the quality of the results
<<Writing 94 skew faces to set skewFaces
Coupled point location match (average 0) OK.

Failed 4 mesh checks.

End

I am attaching the full cylindrical computational domain which is giving me error in OpenFOAM:
Attachment 25660

It was gained from this half cylindrical rotation:
Attachment 25661

I am really out of clue. I would appreciate any help

taxalian September 28, 2013 03:32

Hi Naruto,

Try using Openfoam as solver in Pointwise. It should work fine and you can avoid the conversion of mesh from fluent to Openfoam. Simply specify the proper boundary condition in Pointwise after choosing OF as solver.

good luck.

Naruto September 28, 2013 04:40

Hello,
I tried what u suggested too. But it did not work :(

taxalian September 28, 2013 06:37

Code:

***High aspect ratio cells found, Max aspect ratio: 1.35622e+294, number of cells 36
<<Writing 36 cells with high aspect ratio to set highAspectRatioCells
Minumum face area = 4.81265e-14. Maximum face area = 0.00279988. Face area magnitudes OK.
Min volume = 1.66667e-300. Max volume = 4.86646e-05. Total volume = 1.3839. Cell volumes OK.
Mesh non-orthogonality Max: 111.714 average: 20.6478
*Number of severely non-orthogonal faces: 18175.
***Number of non-orthogonality errors: 432.
<<Writing 18607 non-orthogonal faces to set nonOrthoFaces
***Error in face pyramids: 191 faces are incorrectly oriented.
<<Writing 191 faces with incorrect orientation to set wrongOrientedFaces
***Max skewness = 11.0435, 94 highly skew faces detected which may impair the quality of the results
<<Writing 94 skew faces to set skewFaces

Hi Naruto,
By looking at the errors, you have to locally check the skewness of your badly shaped cells that seems to be incorrectly oriented resulting in wrongly oriented Faces. Make sure that you make right handed grid in Pointwise and then export to the desired solver format.

taxalian September 28, 2013 06:39

Hi Naruto,
Please see this thread to make right handed grid, this might help you:

http://www.cfd-online.com/Forums/poi...se-fluent.html

Naruto September 28, 2013 07:13

2 Attachment(s)
I think I did not describe my problem correctly. This is my usual mesh:
Attachment 25677
I checked this mesh separately in OpenFOAM with the checkMesh utility. There was absolutely no error. It is a good quality mesh.
Then I just mirrored this mesh and made it a full cylinder like this:
Attachment 25678
When I transferred this mesh in OpenFOAM and checked it using CheckMesh, it was a disaster. :(
I am really not getting any clue. Please note that I applied the same procedure in pointwise v16 R3 previously. It just worked fine. I used the same technique for like 2-3 months. It was just fine. The problem started in the newer version of pointwise.
I have also used the tools provided by pointwise to examine my meshing. I did not find any error. As you can see from the log file message of openfoam at some points the aspect ratio is e+26. :eek:
How could even it be possible? In pointwise examine utility the maximum aspect ratio is only 78.
I have also taken a look to the link that you posted. But my mesh in actually 3-Dimensional. :confused:

dgarlisch September 30, 2013 11:12

Please Contact Pointwise Support!
 
This may NOT be a user error. There may be a bug in v17.

Please contact Pointwise tech support or your distributor's tech support. They will be the best way to get this figured out.

It will speed things up if you can send both the original and the mirrored PW grid file to support so we can repeat the bug.

Technical Support
1-800-4PTWISE
support@pointwise.com
www.pointwise.com/support


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