CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

3D-mesh Gambit.....

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   March 8, 2003, 15:22
Default 3D-mesh Gambit.....
  #1
SHR
Guest
 
Posts: n/a
Hi All,

I am trying to generate a complex 3D mesh in Gambit 2.0, in which there is a tank having bottom face as irregular (like undulating ground and not a plane surface) surface and other faces are planer faces.

I coud mesh it and export the mesh successfully, but, in FLUENT 6.0 I am getting the messages " Grid Check Failed" and "NonPositive Volumes Existed" and as I tried to iterate it showed DIVERGENCE.

Actually in Gambit I created only two volumes which I think are Positive only. So where from the non-postive volums came???

I also do not know what is non-postive volume??

Plz. help me find what must be wrong??

Waiting for reply.....

SHR

  Reply With Quote

Old   March 10, 2003, 02:01
Default Re: 3D-mesh Gambit.....
  #2
Michelle
Guest
 
Posts: n/a
Did you check your grid after meshing in GAMBIT? It's probably due to the skewness of the mesh.
  Reply With Quote

Old   March 10, 2003, 05:14
Default Re: 3D-mesh Gambit.....
  #3
ccc
Guest
 
Posts: n/a
hi,SHR

which kind of cell,hex cell or tera cell in your mesh?
  Reply With Quote

Old   March 10, 2003, 07:46
Default Re: 3D-mesh Gambit.....
  #4
Chris
Guest
 
Posts: n/a
I agree with Michelle. Go check the grid using Gambit. (It's in the same position as the icon for information-volume-mesh, except you have to click the right mouse button) Run a check on all your volume meshes. Gambit should report to you which volume meshes have the problem (e.g negative vol etc)
  Reply With Quote

Old   March 14, 2003, 07:03
Default Re: 3D-mesh Gambit.....
  #5
Yazid
Guest
 
Posts: n/a
Dear Mr. SHR

By this time, I think you have resolved your problem.

I would like to share with exprience with non-positive volume message exist. I did exprience a similar case with you.

Here are what I did to fix the problem.

1. The non-positive message will appear in the Fluent

not in Gambit when you deal with virtual volumes. 2. I did some experiments in gambit and read the

mesh to Fluent 3. I deleted suspected volumes, especially virtual

volumes and read the mesh into the Fluent 4. At the end I found what the problem. The problem

was the existence of two volumes, which should be

only one volume. This volume was the virtual

volume. I deleted this volume and recreated

a single volume. 5. I my self do not understand, what is the

physical meaning of non-positive volume.

You must take a good care if you work with virtual volumes. Here is the tip, if you find something that make you frustrated, do the remedy by omitting the suspected volumes, and read the new mesh to the FLUENT, at the end, you will find the cause of the problem and you can fix the problem too.

Regard Yazid Bindar

  Reply With Quote

Old   March 17, 2003, 08:06
Default Re: 3D-mesh Gambit.....
  #6
SHR
Guest
 
Posts: n/a
HI all,

Thanx Michelle, ccc, Chris, & Yazid!! for your replies.

I did check the grid(mesh) in Gambit, as U have suggested, but I did not get any clue/warning in Gambit regarding Negative Volume.

Still I am trying to fix the problem.

Regarding Mesh Check in Gambit, I do not know whether I could check it properly, as I doubt now, as to what is the RIGHT PROCESS OF CHECKING THE MESH in GAMBIT.

Please let me know the same in detail so that I can fix this problem.

Dear Yazid, my geometry does not include any Virtual Volume.

Waiting for HELP..

  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
snappyHexMesh won't work - zeros everywhere! sc298 OpenFOAM Native Meshers: snappyHexMesh and Others 2 March 27, 2011 21:11
Icemcfd 11: Loss of mesh from surface mesh option? Joe CFX 2 March 26, 2007 18:10
Successive Mesh in Gambit ashish FLUENT 0 April 28, 2006 00:42
How to mesh a circle by Gambit? Zhengcai Ye FLUENT 5 March 24, 2006 02:04
Mesh import from gambit Kaushik Balakrishnan (Balakrishnan) OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 5 April 21, 2005 13:42


All times are GMT -4. The time now is 04:09.