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mesh check failed / degenerated contact points

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Old   April 16, 2010, 13:26
Default mesh check failed / degenerated contact points
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Hi all,

my first post here, so please be patient with me

As a new Fluent(12.1.4) user (most of the time i am working with ADINA-F) i
maybe struggle with a problem anyone else has had before me and is willing to help.

I successfully imported a NASTRAN file (mesh (~4Mio elements) generated using 3-matic out of µXCT data) and made a mesh check. Unfortunately the mesh check failed with the warning
"37 degenerated contact points identified.
To print out a list of the contact points call (print-contact-points)"

(i have no negative volume elements, btw)

1) is this warning a problem?
2) fluent faces me with an invalid command error when trying to use the proposed command??

Thx a lot in advance for any answers (and sorry for the long post)

best
shohin
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Old   February 22, 2011, 09:24
Default print contact points
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hi all,

I have the same problem..

i dont have any errors in ICM mesh check...
i import the mesh into Fluent V12 and i always have contact point errors????

The problem is only in Fluent V12
in 6.3 are no errors?? how can that be??

I did not find a description for that f.... error

THX for Help
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Old   February 22, 2011, 12:26
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Try reading in double precision solver in case you are not doing so already.
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Old   May 26, 2011, 06:45
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I find a way to fix this problem...although not smart. input mesh, check, you'll see the warnning message, and it tells you the contact point. then, use mesh/polyhedra/convert domain. convert all the suface tri-mesh to polyhedra.
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Old   June 22, 2011, 09:08
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I had the same problem and i had wrote "(print-contact-points)" in the GUI
-> Fluent gave me the name and localisation of 10 degenerated points. Then with GAMBIT i solved the problem !!!

Or second solution :

"Mesh Check now reports the existence of degenerated contact points created during mesh generation. These are nodes that are incorrectly shared by coincident, uncoupled wall boundaries. If degenerate contact points are detected, Node-based Gradient reconstruction should not be used in the simulation. To avoid errors in the solution, either the mesh should be corrected in the preprocessor to eliminate these nodes, or Least Square Gradient reconstruction should be used instead of Node-based Gradients."
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Old   September 27, 2011, 01:53
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Quote:
Originally Posted by pipin View Post
I had the same problem and i had wrote "(print-contact-points)" in the GUI
-> Fluent gave me the name and localisation of 10 degenerated points. Then with GAMBIT i solved the problem !!!

Or second solution :

"Mesh Check now reports the existence of degenerated contact points created during mesh generation. These are nodes that are incorrectly shared by coincident, uncoupled wall boundaries. If degenerate contact points are detected, Node-based Gradient reconstruction should not be used in the simulation. To avoid errors in the solution, either the mesh should be corrected in the preprocessor to eliminate these nodes, or Least Square Gradient reconstruction should be used instead of Node-based Gradients."

Pipin,

Can you tell me how gambit was used to repair the degenerate points? I have not been able to identify any options in gambit for that.

Thanks
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Old   November 11, 2011, 03:08
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yes.
how can gambit be useful according to same problem?
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Old   January 24, 2013, 02:28
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Quote:
Originally Posted by shan1102 View Post
I find a way to fix this problem...although not smart. input mesh, check, you'll see the warnning message, and it tells you the contact point. then, use mesh/polyhedra/convert domain. convert all the suface tri-mesh to polyhedra.
do it have the effect? please tell me ,thank you
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Old   January 24, 2013, 02:28
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Quote:
Originally Posted by anupam.akolkar View Post
Pipin,

Can you tell me how gambit was used to repair the degenerate points? I have not been able to identify any options in gambit for that.

Thanks
sure? thanks
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Old   August 26, 2013, 17:53
Default ChecK MEsh Failed in Fluent
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Hi All,

I have exported my mesh from ICEM to FLUENT and faced with these errors:

WARNING: Mesh check failed.

To get more detailed information about the mesh check failure
increase the mesh check verbosity via the TUI command
/mesh/check-verbosity.

Any help would be appreciated.
Thanks,
Amir
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Old   August 26, 2013, 18:01
Default Cells have only wall faces .... ?
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After checking the mesh I got this errror.

"WARNING: 35 cell(s) have only wall faces..................."

Anybody know how I can fix it?
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Old   August 26, 2013, 21:03
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Quote:
Originally Posted by Amir1 View Post
After checking the mesh I got this errror.

"WARNING: 35 cell(s) have only wall faces..................."

Anybody know how I can fix it?
your mesh is not good in icem,you must check it,and get mesh again.
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Old   August 26, 2013, 21:04
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Quote:
Originally Posted by Amir1 View Post
Hi All,

I have exported my mesh from ICEM to FLUENT and faced with these errors:

WARNING: Mesh check failed.

To get more detailed information about the mesh check failure
increase the mesh check verbosity via the TUI command
/mesh/check-verbosity.

Any help would be appreciated.
Thanks,
Amir
the quality of your mesh is not very good ,so you can try again
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Old   August 27, 2013, 16:48
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Hi,

I have tried "Check Mesh" there are lots of errors which I could ignore or create a new subset and for some of them I could fix them.

Unfortunately, none of them worked!

Do you know how I can have a good mesh for the curvature attached to a straight surface?
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Old   August 28, 2013, 01:54
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Quote:
Originally Posted by Amir1 View Post
Hi,

I have tried "Check Mesh" there are lots of errors which I could ignore or create a new subset and for some of them I could fix them.

Unfortunately, none of them worked!

Do you know how I can have a good mesh for the curvature attached to a straight surface?
you must have separate grid between them,and define appropriate grid refinement.
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Old   August 28, 2013, 15:18
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Hi,

I did the delauny mesh on the robust mesh refinement, smoothing, mech checking but the problem still exists!
The problem is mainly multiple edges ...

Can you please explain how I can have separate grid ?

Amir
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Old   April 11, 2014, 22:32
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it does not work.
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