[ICEM] Repairing bad volume elements

siw · September 25, 2013, 02:50

Hi,

I'm making a tetra/prism mesh and as is usually the case the prisms have greatly deteriorated the quality of regions of tetra cells. No amount of smoothing (with the various options) will improve these tetra cells which I've put into a subset. So I tried the Repair Mesh > Remesh Bad Elements but this does nothing because these are tetra cells and not surface tri or quad. I thought about just deleteing these bad cells (and maybe 1 layer around them just to be on the safe side) and getting ICEM to remesh the void in the mesh. Has anyone done that and had success or suggest an alternative? BTW, I make the prisms based on PSYMN's tetra/prism presentation.

Thanks

diamondx · September 25, 2013, 15:57

what are the steps you follow to generate your tetra/prism ? have you tried an alternative way ?

siw · September 26, 2013, 02:20

I make the tetra/prism mesh by:

1) Make octree volume mesh. Delete volume elements. Check mesh. Smooth until quality does not improve.
2) Make Delaunay volume mesh. Check mesh. Smooth until quality does not improve.
3) Make floating prism mesh. Check mesh. Smooth quality with PENTA on < 0.05. Smooth with PENTA frozen.
4) Split and redistribute prisms.
5) Get annoyed when ICEM deteriorates tetra mesh after prism generation. Fight and lose against ICEM when trying to repair bad tetra elements to improve quality.

The only alternative method I have tried is not to float the prisms, but rather specifiy a first layer height and total number of layers. That makes the mesh even worse and pyramids are made.

diamondx · September 26, 2013, 14:05

yeah you are doing good, SOMETIMES, floating instead of frozen gets me a better mesh, I don't know why, and sometimes, smoothing everything get me a better mesh also. may be you should try it. but in the end, you can't do nothing but keep the number of those bad elements as small as possible

Luis12 · January 8, 2014, 14:42

Guessing this has been sorted...

Could we have a link to this Tetra/prism mesh presentation please.

Thanks

Far · January 9, 2014, 02:19

here is the link http://www.cfd-online.com/Forums/ans...efinement.html

September 25, 2013, 02:50	Repairing bad volume elements	#1
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 733 Rep Power: 25	Hi, I'm making a tetra/prism mesh and as is usually the case the prisms have greatly deteriorated the quality of regions of tetra cells. No amount of smoothing (with the various options) will improve these tetra cells which I've put into a subset. So I tried the Repair Mesh > Remesh Bad Elements but this does nothing because these are tetra cells and not surface tri or quad. I thought about just deleteing these bad cells (and maybe 1 layer around them just to be on the safe side) and getting ICEM to remesh the void in the mesh. Has anyone done that and had success or suggest an alternative? BTW, I make the prisms based on PSYMN's tetra/prism presentation. Thanks

September 25, 2013, 15:57		#2
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	what are the steps you follow to generate your tetra/prism ? have you tried an alternative way ? __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

September 26, 2013, 14:05		#4
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	yeah you are doing good, SOMETIMES, floating instead of frozen gets me a better mesh, I don't know why, and sometimes, smoothing everything get me a better mesh also. may be you should try it. but in the end, you can't do nothing but keep the number of those bad elements as small as possible __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

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September 26, 2013, 02:20		#3
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 733 Rep Power: 25	I make the tetra/prism mesh by: 1) Make octree volume mesh. Delete volume elements. Check mesh. Smooth until quality does not improve. 2) Make Delaunay volume mesh. Check mesh. Smooth until quality does not improve. 3) Make floating prism mesh. Check mesh. Smooth quality with PENTA on < 0.05. Smooth with PENTA frozen. 4) Split and redistribute prisms. 5) Get annoyed when ICEM deteriorates tetra mesh after prism generation. Fight and lose against ICEM when trying to repair bad tetra elements to improve quality. The only alternative method I have tried is not to float the prisms, but rather specifiy a first layer height and total number of layers. That makes the mesh even worse and pyramids are made.

January 8, 2014, 14:42		#5
Luis12 New Member Luis Join Date: Nov 2013 Posts: 5 Rep Power: 12	Guessing this has been sorted... Could we have a link to this Tetra/prism mesh presentation please. Thanks

January 9, 2014, 02:19		#6
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	here is the link http://www.cfd-online.com/Forums/ans...efinement.html