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

Axis boundary condition.

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 25, 2012, 11:12
Default Axis boundary condition.
  #1
A7A
Member
 
AHMAD
Join Date: Apr 2012
Posts: 53
Rep Power: 5
A7A is on a distinguished road
Hi,

When i try to make axis boundary condition to solve an axissymmetric problem Fluent gives me this warning:

Warning: non-positive volumes exist.

this is a picture of my mesh.

Thank you.
Attached Images
File Type: jpg mesh.jpg (47.9 KB, 11 views)
A7A is offline   Reply With Quote

Old   April 25, 2012, 12:40
Default
  #2
A7A
Member
 
AHMAD
Join Date: Apr 2012
Posts: 53
Rep Power: 5
A7A is on a distinguished road
Any solutions?
A7A is offline   Reply With Quote

Old   April 25, 2012, 13:41
Default
  #3
Senior Member
 
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 594
Rep Power: 11
LuckyTran is on a distinguished road
Quote:
Originally Posted by A7A View Post
Hi,

When i try to make axis boundary condition to solve an axissymmetric problem Fluent gives me this warning:

Warning: non-positive volumes exist.

this is a picture of my mesh.

Thank you.
When does this error pop up? When you read the mesh, check the mesh, or choose axissymmetric?

For axissymmetric problems, the axis of symmetric is defaulted and can only be set to the x-axis. From your drawing, this seems to be the case.

Non-positive volume error means that you have negative cell volumes. It is a meshing error and you need to correct your mesh. Usually it is caused by bad cells. Not sure how this would pertain though to a 2D mesh.

Last edited by LuckyTran; April 25, 2012 at 16:25.
LuckyTran is offline   Reply With Quote

Old   April 25, 2012, 16:17
Default
  #4
Member
 
Join Date: Nov 2011
Location: Czech Republic
Posts: 95
Rep Power: 5
Sixkillers is on a distinguished road
Also for asymmetrical boundary condition your whole geometry has to be above x axis. When it is not, this message appears. You can quickly fix it by rotating your mesh in Fluent (under Mesh -> Rotate).
Sixkillers is offline   Reply With Quote

Old   April 25, 2012, 17:39
Default
  #5
A7A
Member
 
AHMAD
Join Date: Apr 2012
Posts: 53
Rep Power: 5
A7A is on a distinguished road
Thank you for all of your replies it was so helpful.
A7A is offline   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
Boundary Conditions Thomas P. Abraham Main CFD Forum 20 July 7, 2013 05:05
Setting outlet Pressure boundary condition using CAFFA code Mukund Pondkule Main CFD Forum 0 March 16, 2011 04:23
Domain Imbalance HMR CFX 3 March 6, 2011 21:10
asking for Boundary condition in FLUENT Destry FLUENT 0 July 27, 2010 00:55
How to set boundary condition in Fluent for the fo Peiyong FLUENT 1 November 10, 2006 12:44


All times are GMT -4. The time now is 10:47.