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-   -   [ICEM] problem when reading mesh (http://www.cfd-online.com/Forums/ansys-meshing/116263-problem-when-reading-mesh.html)

yorelchr April 16, 2013 06:03

problem when reading mesh
 
Hi everyone,


when I try to read my mesh (done with ICEM) into Fluent, I have the following message :

"Cell Centroid is xc -28.749603 yc 5.334576 zc 0.206958
WARNING: no face with given nodes. Thread 35, cell 4905"

how can I deal with it? what does it mean exactly?

Thanks for any clue...

PS: another question. Has anyone of you already had the problem that, when loading the blocks, appear thousands of blocks in any directions !!! it is not the first time for me, is it a bug from ICEM?

yorelchr

RodriguezFatz April 16, 2013 06:51

Did you use the "check mesh" utility in ICEM? For me - any error that appeared in Fluent - was shown there, too.

Far April 16, 2013 08:55

Quote:

Originally Posted by yorelchr (Post 420870)
Hi everyone,


when I try to read my mesh (done with ICEM) into Fluent, I have the following message :

"Cell Centroid is xc -28.749603 yc 5.334576 zc 0.206958
WARNING: no face with given nodes. Thread 35, cell 4905"

how can I deal with it? what does it mean exactly?

Thanks for any clue...

PS: another question. Has anyone of you already had the problem that, when loading the blocks, appear thousands of blocks in any directions !!! it is not the first time for me, is it a bug from ICEM?

yorelchr

There are many reasons to get this problem. First check your mesh in ICEM and then take it to Fluent

As far as your last comment: Turn on and then turn off VORFN

yorelchr April 16, 2013 09:58

thank you very much for your replies.
I have chechek the mesh, but I had some errors I couldn't understand, I had the possibility to put everything in a set or continue, no way to fix?
Well, I am starting again from the geometry, put away blocking and mesh.

Is it ok if one does the blocks not anly with surfaces but also points and curves, will it give me problems later? (I mean, sometimes, I don't have any surface and instead of always creating new ones, I ask ICEM to make the block an give him surfaces but also points or curves to determine where I want it).

Thanks again.

RodriguezFatz April 16, 2013 10:02

If you run the "check mesh" and an error appears, ICEM will highlight the incorrect cells. Often, you can find some problems in your blocking here. No need to remesh everything. Please post a picture of the highlighted cells and of the blocking.

yorelchr April 16, 2013 19:08

Ciao Rodriguez,

I have cancelled the previous blocks...I've been "fighting" with ICEM for days and had too much files in the computer. So I've started again from geometry but I'm quite sure there will be problems when exporting into FLUENT, so I keep in mind your advice and probably I will post the "errors" tomorrow :-) ...I think I miss Gambit !!!!

Thank again

yorelchr

RodriguezFatz April 17, 2013 02:57

I know. Sometimes ICEM does strange things... Maybe I am the reason for that, but it looks more like a bug. That's when I remesh, too.
I never used Gambit, but ICEM seems to be the perfect grid generator. Just get used to it and you will like it.

yorelchr April 17, 2013 09:37

well, for now, the more I use it, the more I "hate" it :-)

I'm still on the same geometry and mesh.
Is it possible to have 2 adjacent blocks with different mesh? sometimes it seems to be possible, but sometimes not. How can I know what are the situations in which it is possible?

thank you so much in advance!!!

RodriguezFatz April 17, 2013 09:40

Maybe someone has to correct me, but I think it is not possible. Two adjacent blocks have a common edge and both use the edge's parameters. Can you show a screenshot if that happes?
If you want to have such a thing (non-conformal mesh) you have to convert both blocks seperatly and merge the two meshes I think...

Also: Just upload a screenshot of your setup / blocking. You will get excellent tips from people here normally.

yorelchr April 17, 2013 10:24

2 Attachment(s)
ok, I have put 2 screen-shots: one for the blocking, the other one for the mesh.
The number of nodes are really bad, but I'm really fed up to have to re-renter them each time (no way ICEM memorize them???) .
Well, I have problems with the upper blocks. The 2 smalls, are ok, but when I add the other one next to them, I have this strange mesh....and the mesh of the 2 small is not ok anymore.
I don't know if these pictures give an idea...
I should then do separate geometries and mesh each time I have a different mesh and merge at the end?

PS: before canceling the blocks (first I have built all the blocking but since I have problems, I've canceled them), and many times, it was ok with 2 different meshes, that's why I was wondering if it couldn't be ok under some circumstances...)

yorelchr April 17, 2013 13:00

ok, I have divided the domain. For the moment, I just have something that is topologically equivalente to a cube, just one block, meshed, ok...FLUENT doesn't read the mesh !!! I think it is a problem of periodicity (there is no explanation in the error message...), but I don't understand how to solve that. How can I just cancel all periodic pair of points so I can do it from the beginning?

Far April 17, 2013 15:13

yorelchr: did you make the association?

RodriguezFatz April 17, 2013 15:20

I will have a closer look tomorrow, but don't you have a triangle-shaped block in the middle?

Far April 17, 2013 15:49

Take a look here: http://www.cfd-online.com/Forums/ans...s-meshing.html

http://www.cfd-online.com/Forums/att...sh-meshpic.jpg

RodriguezFatz April 17, 2013 15:58

But that's not what he did, right? His block looks like it has a triangular face...

Far April 17, 2013 16:03

Yes he did not. He need to implement quarter o-grid (or Y-grid). Also I see there is association problem too.

RodriguezFatz April 17, 2013 16:05

Looks like christine gets some homework ;)

diamondx April 17, 2013 16:52

i have a video on how to do this mesh in icem in this exact geometry... let me know if someone needs it

yorelchr April 18, 2013 05:00

Thank s to all of you for your replies.
So, I will try to explain better what I'm supposed to do.
I'm working on a geometry very similar to the one posted by Far.
It's already all meshed etc...but it has too many cells so I have to reduce the domain (there would be a big part before that I put away and I will use profiles from simulations already performed on the entire domain).
I want to avoid the very thin part and for that I would like to use non-conformal mesh.
The association for periodicity have been already done by the person who did the entire geometry and mesh and I don't know how to cancel and do again.
For now, I'm working on a small part (I will merge with Fluent the different meshes) but even that small part, Fluent does not want to read it. What is wrong in my way of doing :
1. creating geometry
2. defining body
3. defining different parts, one with all points and curves
4. creating block only considering surfaces
5. meshing
6. defining boundaries

Can someone explain me the exact way to establish periodicity?
Thanks a lot

Christine

diamondx April 18, 2013 11:37

When you convert the mesh to unstructured, under edit tab run check mesh, to look for possible error


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