[ANSYS Meshing] Negative Cell Volumes

donkey86 · June 14, 2011, 04:05

Hi there!

I am still trying to mesh a pipe with a radial inlet. Running quality checks
I get negative cell volumes on most of the edges. I tried adapting the spacing and ratio values but still no improvement. The associations of edges and vertices look fine as far as I know. Can somebody help me please?

donkey86 · June 14, 2011, 04:09

there you have a screenshot

user_of_cfx · June 14, 2011, 06:33

I can't see the cross-section very well, are you using an O grid? It seems that where the inlet is the mesh gets unusually distorted, or maybe it's the angle with which I'm looking at it. Usually an O-grid will solve most of the problems near the edges. If the distortion I see is where the negative quality elements are, then this is a tell-tale sign that an O-grid is needed.

If you do have an O-grid and still get this, how did you create your geometry? Sometimes trying a different approach to get the same geometry solves some problems.

Hope it helps.

donkey86 · June 16, 2011, 02:26

thanks for your help, I tweaked the geometry and solved my problems. now there is a smal amount of cells left, but I i am hopefull to get rid of them soon.

June 14, 2011, 04:05	Negative Cell Volumes	#1
donkey86 New Member Join Date: Jun 2011 Posts: 5 Rep Power: 14	Hi there! I am still trying to mesh a pipe with a radial inlet. Running quality checks I get negative cell volumes on most of the edges. I tried adapting the spacing and ratio values but still no improvement. The associations of edges and vertices look fine as far as I know. Can somebody help me please?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[blockMesh] BlockMesh FOAM warning	gaottino	OpenFOAM Meshing & Mesh Conversion	7	July 19, 2010 14:11
Cells with t below lower limit	Purushothama	Siemens	2	May 31, 2010 21:58
[blockMesh] Axisymmetrical mesh	Rasmus Gjesing (Gjesing)	OpenFOAM Meshing & Mesh Conversion	10	April 2, 2007 14:00
[Commercial meshers] Trimmed cell and embedded refinement mesh conversion issues	michele	OpenFOAM Meshing & Mesh Conversion	2	July 15, 2005 04:15
Warning 097-	AB	Siemens	6	November 15, 2004 04:41

June 14, 2011, 06:33		#3
user_of_cfx Member Christa Join Date: Apr 2011 Posts: 53 Rep Power: 15	I can't see the cross-section very well, are you using an O grid? It seems that where the inlet is the mesh gets unusually distorted, or maybe it's the angle with which I'm looking at it. Usually an O-grid will solve most of the problems near the edges. If the distortion I see is where the negative quality elements are, then this is a tell-tale sign that an O-grid is needed. If you do have an O-grid and still get this, how did you create your geometry? Sometimes trying a different approach to get the same geometry solves some problems. Hope it helps.

June 16, 2011, 02:26		#4
donkey86 New Member Join Date: Jun 2011 Posts: 5 Rep Power: 14	thanks for your help, I tweaked the geometry and solved my problems. now there is a smal amount of cells left, but I i am hopefull to get rid of them soon.