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

non-positive volumes in mesh

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 25, 2008, 06:26
Default non-positive volumes in mesh
  #1
Muhammad Usman Qureshi
Guest
 
Posts: n/a
Hi,

I have some non-positive volumes in my volume mesh. i am trying to run an inviscid simulation. Will this cause some error and will it cause Fluent to stop.

Many Thanks,
  Reply With Quote

Old   March 25, 2008, 08:46
Default Re: non-positive volumes in mesh
  #2
Davide
Guest
 
Posts: n/a
I think that you've got to review the mesh, maybe there are some curve surfaces wrong meshed. Try to look your geometry with the shade option in gambit to control if there are surfaces that look "strange"
  Reply With Quote

Old   March 26, 2008, 08:46
Default Re: non-positive volumes in mesh
  #3
Daniel Tanner
Guest
 
Posts: n/a
Most problems occur because of a poorly defined initial surfaces. Check these, paying particular attention to areas of high curvature.

Are you using a prism layer? Check to see if the prism is collapsing (use smaller elements and see if the problem persists). You could try creating a mesh with no prism layer, just to see if it is boundary elements are causing the problem.

Are you using TGrid or Gambit? You can use the "examine mesh" button in Gambit (the magnifying glass on the bottom right of the Gambit window) to see where the problem elements are located. Try creating finer meshes and see if the problems persist and if they occur in the same locations. In TGrid you can do the same using "display-> grid".

Hope this helps.
  Reply With Quote

Old   March 28, 2008, 15:57
Default Re: non-positive volumes in mesh
  #4
Paul
Guest
 
Posts: n/a
Could try increasing your spacing in the meshing procedure. Is your model geometrically very complicated?
  Reply With Quote

Old   April 1, 2008, 11:45
Default Re: non-positive volumes in mesh
  #5
Míša Milakovová
Guest
 
Posts: n/a
Hi, I had the same problem with 3D mesh. I moved all volumes to positive axis. So, try it too.
  Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
help! how to find out the non-positive volumes? showwa FLUENT 0 August 30, 2008 02:22
non-positive volumes exist DavidC FLUENT 2 November 15, 2005 06:57
non-positive volumes john FLUENT 9 March 12, 2001 07:17
non-positive volumes Javier Fernandez FLUENT 5 August 29, 2000 00:37
non positive volumes pankaj shukla FLUENT 4 December 6, 1999 09:42


All times are GMT -4. The time now is 18:20.