Block structured hexagonal mesh vs automated tetra mesh inside Workbench for CFD

Chander · November 26, 2011, 15:52

Hi,

I have been using CFX for the last one year and so far I have always used block-structured hexagonal meshes, generated in ICEM CFD, for my CFX simulations.
Now I want to use Workbench to parametrise my geometry and explore the effects of geometrical changes on CFD results. I am not very familiar with Workbench.
Is doing a block structured hexagonal meshing possible inside Workbench. I have Ansys versions 12.1 and 13.0 on my system. I could not find any tutorials related to this for both versions. I found a tutorial named "Workbench Integration" for ICEM CFD 11.0 but I could not do that tutorial in versions 12.1 or 13.0 as the tutorial mentions a totally different GUI.

If there is no way to perform block structured hexagonal meshing in Workbench, then I will have to use the automated Tetra meshing available in Workbench 12.1 or 13.0. I have never used automated tetra mesh before and I am not sure about using it as I have heard that structured hexagonal mesh is always more accurate for fluid flow.

In summary, my questions are:
a) If it is possible, then how to do and automate a block structured hexagonal meshing (similar to ICEM CFD) inside Workbench? Is there any tutorial for this?

b) How accurate it is in general to use automated tetra meshing for fluid flow instead of block structured tetra meshing?

Thanks for your inputs!

ghorrocks · November 27, 2011, 05:14

You can do hex meshes in WB, the mapped mesh feature and sweep meshes are useful for this. But they are no where near as powerful and ICEM hexa and frustrating to use in my opinion. But if you want to parameterise your geometry it is easiest way.

You can also parameterise ICEM I think, especially in V13.

Chander · November 27, 2011, 17:00

Thanks Glen for your reply.

I could not find anything inside ICEM 13 to parameterise my geomtry. May be recording and relaying script can work?

However, the main issue is that I want to do a ggeometry shae optimization using CFD and i is for that purpose I want to use Workbench by using its response surface optimization feature.

I think ICEM cannot be included as a module inside Workbench and so , even if parameterisation is possible in ICEM, it will not be useful.

Is there any other way, apart from Workbench, by which I can combine a geometry and meshing software, a CFD solver like CFX and an optimizer to automate the optimization process?

ghorrocks · November 27, 2011, 17:24

ICEM is in WB. Have a look on the forum about remeshing in ICEM. But you should talk to CFX support about this, they will put you on the right track quickest.

Optimisation can be done by many methods, none of them straight forward. The whole point of WB was to make this sort of thing easier.

November 26, 2011, 15:52	Block structured hexagonal mesh vs automated tetra mesh inside Workbench for CFD	#1
Chander Senior Member Join Date: Oct 2010 Location: Zurich Posts: 176 Rep Power: 16	Hi, I have been using CFX for the last one year and so far I have always used block-structured hexagonal meshes, generated in ICEM CFD, for my CFX simulations. Now I want to use Workbench to parametrise my geometry and explore the effects of geometrical changes on CFD results. I am not very familiar with Workbench. Is doing a block structured hexagonal meshing possible inside Workbench. I have Ansys versions 12.1 and 13.0 on my system. I could not find any tutorials related to this for both versions. I found a tutorial named "Workbench Integration" for ICEM CFD 11.0 but I could not do that tutorial in versions 12.1 or 13.0 as the tutorial mentions a totally different GUI. If there is no way to perform block structured hexagonal meshing in Workbench, then I will have to use the automated Tetra meshing available in Workbench 12.1 or 13.0. I have never used automated tetra mesh before and I am not sure about using it as I have heard that structured hexagonal mesh is always more accurate for fluid flow. In summary, my questions are: a) If it is possible, then how to do and automate a block structured hexagonal meshing (similar to ICEM CFD) inside Workbench? Is there any tutorial for this? b) How accurate it is in general to use automated tetra meshing for fluid flow instead of block structured tetra meshing? Thanks for your inputs!

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November 27, 2011, 05:14		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	You can do hex meshes in WB, the mapped mesh feature and sweep meshes are useful for this. But they are no where near as powerful and ICEM hexa and frustrating to use in my opinion. But if you want to parameterise your geometry it is easiest way. You can also parameterise ICEM I think, especially in V13.

November 27, 2011, 17:00		#3
Chander Senior Member Join Date: Oct 2010 Location: Zurich Posts: 176 Rep Power: 16	Thanks Glen for your reply. I could not find anything inside ICEM 13 to parameterise my geomtry. May be recording and relaying script can work? However, the main issue is that I want to do a ggeometry shae optimization using CFD and i is for that purpose I want to use Workbench by using its response surface optimization feature. I think ICEM cannot be included as a module inside Workbench and so , even if parameterisation is possible in ICEM, it will not be useful. Is there any other way, apart from Workbench, by which I can combine a geometry and meshing software, a CFD solver like CFX and an optimizer to automate the optimization process?

November 27, 2011, 17:24		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	ICEM is in WB. Have a look on the forum about remeshing in ICEM. But you should talk to CFX support about this, they will put you on the right track quickest. Optimisation can be done by many methods, none of them straight forward. The whole point of WB was to make this sort of thing easier.