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-   -   Wrong face orientations after conversion from fluent mesh (http://www.cfd-online.com/Forums/openfoam-meshing-other/61692-wrong-face-orientations-after-conversion-fluent-mesh.html)

stevecollie April 10, 2008 08:21

Hi there, I am a new openFo
 
Hi there,

I am a new openFoam user and am having trouble with fluent3DMeshToFoam

The mesh converts OK, but with a warning:

--> FOAM Warning :
From function boundBox::boundBox(const pointField& points)
in file meshes/boundBox/boundBox.C at line 52
cannot find bounding box for zero sized pointFieldreturning zero

And then when I run checkMesh I get a problem with face orientation:

***Error in face pyramids: 38 faces are incorrectly oriented.
<<Writing 38 faces with incorrect orientation to set wrongOrientedFaces

My grid does include internal walls (split in ICEM) however I have been able to import other grids with internal walls just fine. Also the face numbers in wrongOrientedFaces don't appear to be associated with these patches.

A mesh quality check in ICEM doesn't show any problems and the simulation runs fine in CFX11.

Any advice?

Cheers,
Steve

mattijs April 10, 2008 15:17

Unlikely that there is a probl
 
Unlikely that there is a problem in the conversion. Sounds like your mesh is just not very good and the CFX checker does not pick this up as a problem.

hjasak April 10, 2008 16:05

These meshes are usually broke
 
These meshes are usually broken. When you read them into Fluent, the code will quietly fix the mesh and write it out in a correct form. Try reading in your mesh into fluent and writing it out again (ascii format) and all will be well.

Please let me know,

Hrv

dmoroian April 10, 2008 17:09

I faced similar warnings and e
 
I faced similar warnings and error messages, but the simulation went smoothly.

Dragos

dmoroian April 16, 2008 01:39

Just to show the issue I was t
 
Just to show the issue I was talking about on the previous post:
http://www.cfd-online.com/OpenFOAM_D...ges/1/7356.jpg
It seems the faces are not oriented in the same way, although they are in the same plane.

Dragos

stevecollie April 16, 2008 06:08

Hi there, Unfortunately my
 
Hi there,

Unfortunately my simulation crashes at a floating point exception immediately so I fear my grid issue is more serious.

I have tried with both Fluent3DMeshToFoam and StarToFoam and I believe I basically get the same foam mesh out,.. well the same errors at least. I have previously been running the simulations in CFX and it might be as Hrvoje suggested that CFX was merely repairing the issues. Unfortunately I don't have fluent or star to see if they can repair the issues. At the same time though, the grid passed all the checks in ICEM so it can't be that bad.

In the meantime I am going to try alternative grid generators / gridding strategies.

Thanks for your help,
Steve

tian July 14, 2008 07:20

Hi Steve, did you find a so
 
Hi Steve,

did you find a solution for your case? Whould be nice if you can show me. Thanks

Bye
Thomas


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