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-   -   mesh check failed / degenerated contact points (http://www.cfd-online.com/Forums/fluent/75120-mesh-check-failed-degenerated-contact-points.html)

shohin April 16, 2010 13:26

mesh check failed / degenerated contact points
 
Hi all,

my first post here, so please be patient with me :o

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

BST February 22, 2011 08:24

print contact points
 
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

rkumar310 February 22, 2011 11:26

Try reading in double precision solver in case you are not doing so already.

shan1102 May 26, 2011 06:45

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.

pipin June 22, 2011 09:08

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."

anupam.akolkar September 27, 2011 01:53

Quote:

Originally Posted by pipin (Post 313075)
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

emreg November 11, 2011 02:08

yes.
how can gambit be useful according to same problem?

Striving January 24, 2013 01:28

Quote:

Originally Posted by shan1102 (Post 309326)
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

Striving January 24, 2013 01:28

Quote:

Originally Posted by anupam.akolkar (Post 325717)
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

Amir1 August 26, 2013 17:53

ChecK MEsh Failed in Fluent
 
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

Amir1 August 26, 2013 18:01

Cells have only wall faces .... ?
 
After checking the mesh I got this errror.

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

Anybody know how I can fix it?

Striving August 26, 2013 21:03

Quote:

Originally Posted by Amir1 (Post 448199)
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.

Striving August 26, 2013 21:04

Quote:

Originally Posted by Amir1 (Post 448195)
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

Amir1 August 27, 2013 16:48

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?

Striving August 28, 2013 01:54

Quote:

Originally Posted by Amir1 (Post 448373)
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.

Amir1 August 28, 2013 15:18

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

7799555 April 11, 2014 22:32

it does not work.


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