CFD Online Logo CFD Online URL
Home > Forums > CFX

Negative Mesh Quality

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

LinkBack Thread Tools Display Modes
Old   July 5, 2006, 11:41
Default Negative Mesh Quality
Posts: n/a
I have made a hex mesh for my geometry. The pre-mesh quality(of the blocking) shows 0.3

However, after the mesh is loaded from the blocking, the quality is -0.15. How do I improve the quality?
  Reply With Quote

Old   July 5, 2006, 13:38
Default Re: Negative Mesh Quality
Posts: n/a
You probably have the surface quad mesh selected as well. If you unselect the surface in the parts list, only the quality of the volume elements will be calculated, and that should be the same as your premesh quality.
  Reply With Quote

Old   July 6, 2006, 05:48
Default Re: Negative Mesh Quality
Posts: n/a
Dear Evan,

I checked it out. Even if I only select hexas in the list, the quality is 0. These elements between 0 & 0.05 (72 elements) are causing problems. I am also unable to load the mesh in CFX-Pre because of these bad elements.

If you dont mind, may I send you my block file ?

Thank You,

  Reply With Quote

Old   July 6, 2006, 11:35
Default Re: Negative Mesh Quality
Posts: n/a
Another thing to check is that only the volume parts of interest are selected/active when you convert the Pre-Mesh to Unstructured Mesh.

You should also verify that there are no problems in the Pre-Mesh. When you look at the Pre-Mesh Quality (say the 2x2x2 determinant) set the min to -1 and the max to +1. You may actually have problems in the Pre-Mesh that weren't shown because of limits on the histogram. (It will also show the min and max in small letters in the histogram area itself.)
  Reply With Quote


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
Mesh deformation, negative volume! Turbomachine CFX 12 June 9, 2011 08:05
early stall, poor convergence, and mesh quality everest CFX 2 May 12, 2010 16:27
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55
mesh quality and independency..!?? michelle CFX 0 October 15, 2007 05:50
Quality of extruded mesh in ICEM CFD Andrew CFX 1 December 28, 2006 11:35

All times are GMT -4. The time now is 08:30.