Problem of CFX-pre process big mesh file

novauva · May 8, 2009, 16:15

I have genreated a big mesh of ~6 millions elements using Ansys mesher. But after I imported the mesh into CFX-Pre, the wait time for CFX-pre to complete each operation (such as insert boundary, choose surfaces, etc) is too long to stand (more then 30mins for even a simple operation!) I checked the memory been used for this pre-processing is about 2GB, since my PC has 32GB memory, I don't think the memory is the real reason. My CPU is 3GHz, it should be OK for this pre-processing too. But what's the cause of this slow response and how can I increase the CFX-pre responding speed? Is there any Configuration setting change needed?

Right now, the mesh file looks just like a too heavy load for my CFX-11 to handle, and it should not be the case. Helps are needed! thanks.

bharath · May 8, 2009, 21:19

1)how many interfaces do u have?if number of interfaces are high then the process may be slow down.
2)from which mesher you brought your mesh to CFX.if you brought it from gambit then try the same with ICEM.
3)if You have no off identical meshes and you transformed or copied the mesh
in mesher try it in CFX pre.

novauva · May 8, 2009, 21:49

Yes, My mesh does have many interfaces because I used "pattern" to duplicate many bodies in the model: there are about ten thousand faces that were created and need to impose BCs. Probably that's the reason why pre-processing is so slow. Do you know any efficient way to "batch process the interfaces" in CFX-Pre since many interfaces are of same identity?

I tried to create a name for a selection of interfaces during mesh generation (in ANSYS mesher), but it seems like this "name selection" does not carry over to the CFX-Pre. Any idea? THanks a lot!

bharath · May 9, 2009, 03:56

1)why it is of so much interfaces?does it really needed.try to reduce the no off interfaces.
2)try to bring a single identitical mesh to the CFX pre and pattern it in CFX- Pre.
3)could you attach an image of your geometry.it will help me to suggest you.

ghorrocks · May 10, 2009, 23:22

Hi,

CFX-Pre should be fine with a 6M node simulation. I think the slow behaviour is due to the large number of faces.

Yes, CFX-Pre can be scripted. It is a pretty easy format so should be straightforward to do in this case. Record a session file of doing some operations to see the format.

CFX-Pre renames the faces for several import formats, and I don't think the named selection stuff gets carried over. I think this area has been improved in V12 - it has now been released so you should try on that.

You can also get a speedup by turning some display options off. For instance turning the boundary markers off may improve things.

Glenn Horrocks

novauva · May 11, 2009, 09:19

Thank you Glenn and Bharath for the suggestions above. I think I will have to try CCL for CFX-Pre operations. Bharath mentioned "Pattern a mesh in CFX-pre": Could you instruct me more specifically? I know how to pattern a simple body in "design modeler", but haven't heard about patterning a simple mesh in CFX-Pre. I appreciate your help.

bharath · May 23, 2009, 13:14

Sorry for the delay.pattern in CFX pre is easier step.just bring a single identitical mesh to the pre.then right click on the mesh that u just brought to pre.then click on transformation and specify the direction and distance and no.off instances that you need.don't forget to switch on the glue adjacent meshes.

May 8, 2009, 16:15	Problem of CFX-pre process big mesh file	#1
novauva New Member Join Date: May 2009 Posts: 3 Rep Power: 16	I have genreated a big mesh of ~6 millions elements using Ansys mesher. But after I imported the mesh into CFX-Pre, the wait time for CFX-pre to complete each operation (such as insert boundary, choose surfaces, etc) is too long to stand (more then 30mins for even a simple operation!) I checked the memory been used for this pre-processing is about 2GB, since my PC has 32GB memory, I don't think the memory is the real reason. My CPU is 3GHz, it should be OK for this pre-processing too. But what's the cause of this slow response and how can I increase the CFX-pre responding speed? Is there any Configuration setting change needed? Right now, the mesh file looks just like a too heavy load for my CFX-11 to handle, and it should not be the case. Helps are needed! thanks.

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May 8, 2009, 21:19		#2
bharath Senior Member Bharath kumar Join Date: Apr 2009 Posts: 169 Rep Power: 17	1)how many interfaces do u have?if number of interfaces are high then the process may be slow down. 2)from which mesher you brought your mesh to CFX.if you brought it from gambit then try the same with ICEM. 3)if You have no off identical meshes and you transformed or copied the mesh in mesher try it in CFX pre.

May 8, 2009, 21:49		#3
novauva New Member Join Date: May 2009 Posts: 3 Rep Power: 16	Yes, My mesh does have many interfaces because I used "pattern" to duplicate many bodies in the model: there are about ten thousand faces that were created and need to impose BCs. Probably that's the reason why pre-processing is so slow. Do you know any efficient way to "batch process the interfaces" in CFX-Pre since many interfaces are of same identity? I tried to create a name for a selection of interfaces during mesh generation (in ANSYS mesher), but it seems like this "name selection" does not carry over to the CFX-Pre. Any idea? THanks a lot!

May 9, 2009, 03:56		#4
bharath Senior Member Bharath kumar Join Date: Apr 2009 Posts: 169 Rep Power: 17	1)why it is of so much interfaces?does it really needed.try to reduce the no off interfaces. 2)try to bring a single identitical mesh to the CFX pre and pattern it in CFX- Pre. 3)could you attach an image of your geometry.it will help me to suggest you.

May 10, 2009, 23:22		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Hi, CFX-Pre should be fine with a 6M node simulation. I think the slow behaviour is due to the large number of faces. Yes, CFX-Pre can be scripted. It is a pretty easy format so should be straightforward to do in this case. Record a session file of doing some operations to see the format. CFX-Pre renames the faces for several import formats, and I don't think the named selection stuff gets carried over. I think this area has been improved in V12 - it has now been released so you should try on that. You can also get a speedup by turning some display options off. For instance turning the boundary markers off may improve things. Glenn Horrocks

May 11, 2009, 09:19		#6
novauva New Member Join Date: May 2009 Posts: 3 Rep Power: 16	Thank you Glenn and Bharath for the suggestions above. I think I will have to try CCL for CFX-Pre operations. Bharath mentioned "Pattern a mesh in CFX-pre": Could you instruct me more specifically? I know how to pattern a simple body in "design modeler", but haven't heard about patterning a simple mesh in CFX-Pre. I appreciate your help.

May 23, 2009, 13:14		#7
bharath Senior Member Bharath kumar Join Date: Apr 2009 Posts: 169 Rep Power: 17	Sorry for the delay.pattern in CFX pre is easier step.just bring a single identitical mesh to the pre.then right click on the mesh that u just brought to pre.then click on transformation and specify the direction and distance and no.off instances that you need.don't forget to switch on the glue adjacent meshes.