Split up regions from a .def file

Eistee1024 · July 3, 2018, 13:52

Hello everyone,

I have got a .def file with of a whole cfx setup, so containing mesh, boundarys and everything.
I would now pretty much like to just split some of the 2D regions in the model and would like to alter the roughness on these. All that prefered without remeshing. What is the easiest way to do this?

I found the "Edit Mesh" button in CFX-Pre where I can move surface elements to a new region, but this requieres manual picking if Im not mistaken.
Is there some easier way to split my regions (without loosing the untouched rest of the setup)?
It would be great if there would be some way to split a region by or at a certain location, so that i can make some sort of grid on the existing surface.

Im currently using ANSYS 18.2 but am flexible upwards. ICEM CFD is available but im not yet familiar with it.

Any help is highly apreciatet, thank You in advance!

ghorrocks · July 3, 2018, 19:54

In CFX-Pre you can translate, rotate, scale etc. You can also choose to only use part of the mesh in your model as well. But the mesh regions need to already be set up and it can only operate on whole mesh regions. You cannot sub-divide existing mesh regions.

If you want to split an existing mesh region then your best option is to probably load it into ICEM. ICEM has lots of functions for editing existing meshes.

Eistee1024 · July 23, 2018, 08:34

Hey ghorrocks,
thank you very much for your reply!
I decided to use the 'initialize profile data', where I map wall roughness by location on the interfaces between fluid and solid.

To do so, the user function generated by the 'initialize profile data' was put in an expresseion, where i added the mandatory locators, so my expression looks like

test.Wall Roughness(x,y,z)

I used this expression in the interfaces as the wall roughness.
This method works on some of my parts quiet well. Though it's not working on rotating domains. Neither the wall roughness nor its effects on the wall shear stress can be seen in post. I'm not perfectly shure that the domain rotation is causing this and am nearly out of ideas what to check.
Does anyone else have a clue?

One thing I found interesting: In my test model when defining an expression based on a user function, CFX suggested me test.Wall Roughness while the dot and the following Wall Roughness aren't suggested in my real world project. Is this indicating something?

July 3, 2018, 13:52	Split up regions from a .def file	#1
Eistee1024 New Member Holger Join Date: Oct 2015 Location: Germany Posts: 4 Rep Power: 11	Hello everyone, I have got a .def file with of a whole cfx setup, so containing mesh, boundarys and everything. I would now pretty much like to just split some of the 2D regions in the model and would like to alter the roughness on these. All that prefered without remeshing. What is the easiest way to do this? I found the "Edit Mesh" button in CFX-Pre where I can move surface elements to a new region, but this requieres manual picking if Im not mistaken. Is there some easier way to split my regions (without loosing the untouched rest of the setup)? It would be great if there would be some way to split a region by or at a certain location, so that i can make some sort of grid on the existing surface. Im currently using ANSYS 18.2 but am flexible upwards. ICEM CFD is available but im not yet familiar with it. Any help is highly apreciatet, thank You in advance!

July 3, 2018, 19:54		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	In CFX-Pre you can translate, rotate, scale etc. You can also choose to only use part of the mesh in your model as well. But the mesh regions need to already be set up and it can only operate on whole mesh regions. You cannot sub-divide existing mesh regions. If you want to split an existing mesh region then your best option is to probably load it into ICEM. ICEM has lots of functions for editing existing meshes. Eistee1024 likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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July 23, 2018, 08:34		#3
Eistee1024 New Member Holger Join Date: Oct 2015 Location: Germany Posts: 4 Rep Power: 11	Hey ghorrocks, thank you very much for your reply! I decided to use the 'initialize profile data', where I map wall roughness by location on the interfaces between fluid and solid. To do so, the user function generated by the 'initialize profile data' was put in an expresseion, where i added the mandatory locators, so my expression looks like test.Wall Roughness(x,y,z) I used this expression in the interfaces as the wall roughness. This method works on some of my parts quiet well. Though it's not working on rotating domains. Neither the wall roughness nor its effects on the wall shear stress can be seen in post. I'm not perfectly shure that the domain rotation is causing this and am nearly out of ideas what to check. Does anyone else have a clue? One thing I found interesting: In my test model when defining an expression based on a user function, CFX suggested me test.Wall Roughness while the dot and the following Wall Roughness aren't suggested in my real world project. Is this indicating something?