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-   -   6DOF motion of rigid body in ANSYS-CFX14 (http://www.cfd-online.com/Forums/cfx/121432-6dof-motion-rigid-body-ansys-cfx14.html)

Spring.s July 28, 2013 20:46

6DOF motion of rigid body in ANSYS-CFX14
 
Hi
I want to model a merged body in water flow in CFX and it needs to remeshing. Can I use the ICEM for remeshing in this problem?
The motion of rigid body in this case contains rotation and translation together. Can anyone help me?
Thanks.

ghorrocks July 29, 2013 00:16

Yes, you can remesh using ICEM.

If you explain what you are trying to do maybe we can help you.

Spring.s July 29, 2013 03:50

Thanks Glenn for your response
I want move the merged cubic in the flow that contains translational and "rotational" movement.
I have read that ICEM supports translational movement only, is it true or ICEM is capable to remeshing rotational movement?
What's your suggestion between ICEM and WORKBENCH's remeshing?
Best regards

ghorrocks July 29, 2013 08:05

I have not used either remeshing techniques so cannot answer you. Hopefully some others on the forum can answer this.

singer1812 July 29, 2013 09:33

ICEM can do what you are asking. But the remesh is USER DEFINED.

I assume your motion is not fully prescribed, but rather part of the solution. In that case when you interrupt for a your whatever condition you are interrupting for, send the results file to pre to get the latest geometry, write out a def file, read that def file into icem, convert the mesh to faceted geometry, blow away the new mesh, remesh the geometry, write out the new mesh and continue.

If you dont know ICEM scripting, this can be daunting. Contact ANSYS support for an example.

MUMMED July 31, 2013 12:27

Quote:

Originally Posted by singer1812 (Post 442592)
ICEM can do what you are asking. But the remesh is USER DEFINED.

I assume your motion is not fully prescribed, but rather part of the solution. In that case when you interrupt for a your whatever condition you are interrupting for, send the results file to pre to get the latest geometry, write out a def file, read that def file into icem, convert the mesh to faceted geometry, blow away the new mesh, remesh the geometry, write out the new mesh and continue.

If you dont know ICEM scripting, this can be daunting. Contact ANSYS support for an example.

dear singer
i agree with you that's an option but i think there are more options
i believe workbench re-meshing is more helpful because you don't need watch the solving process and re-meshing works automatically.as far as i know ICEM does not support re-meshing for rotational motion (cfx_ref page 70)
i suppose workbench re-meshing is more general.

Spring.s August 14, 2013 02:38

Quote:

Originally Posted by singer1812 (Post 442592)
ICEM can do what you are asking. But the remesh is USER DEFINED.

I assume your motion is not fully prescribed, but rather part of the solution. In that case when you interrupt for a your whatever condition you are interrupting for, send the results file to pre to get the latest geometry, write out a def file, read that def file into icem, convert the mesh to faceted geometry, blow away the new mesh, remesh the geometry, write out the new mesh and continue.

If you dont know ICEM scripting, this can be daunting. Contact ANSYS support for an example.



Hi Singer1812
Do you mean that I read def file by the ICEM for any remesh of domain and so repeat remeshing?
While after the remeshing step by CFX and stopping solution, don't see rotational movement of body in def file! In other word, geometry returns to the first state and don't remesh for rotational movement.
Best regards

singer1812 August 14, 2013 08:28

You need to pass the geometry through CFXPRE first. ICEM cant read the updated geom after mesh motion in a run. You bring the res file into pre, it will have the right geom update, and then write out a def file that will be pulled into ICEM.

Spring.s August 17, 2013 04:12

Quote:

Originally Posted by singer1812 (Post 445686)
You need to pass the geometry through CFXPRE first. ICEM cant read the updated geom after mesh motion in a run. You bring the res file into pre, it will have the right geom update, and then write out a def file that will be pulled into ICEM.



Hi Singer1812
Thank you for your replay
So, do you tell me for every remeshing process, we must repeat this steps?
Can't it performs automatically?
Best regards

Spring.s August 21, 2013 09:17

Dear Singer1812, I don't know how prepare the script file for send the res file to pre and write out a def file. Can you help me?
Thanks

Spring.s August 21, 2013 09:18

Quote:

Originally Posted by singer1812 (Post 442592)
ICEM can do what you are asking. But the remesh is USER DEFINED.

I assume your motion is not fully prescribed, but rather part of the solution. In that case when you interrupt for a your whatever condition you are interrupting for, send the results file to pre to get the latest geometry, write out a def file, read that def file into icem, convert the mesh to faceted geometry, blow away the new mesh, remesh the geometry, write out the new mesh and continue.

If you dont know ICEM scripting, this can be daunting. Contact ANSYS support for an example.





Dear Singer1812, I don't know how prepare the script file for send the res file to pre and write out a def file. Can you help me?
Thanks

brunoc August 21, 2013 11:43

Quote:

Originally Posted by Spring.s (Post 447157)
Dear Singer1812, I don't know how prepare the script file for send the res file to pre and write out a def file. Can you help me?
Thanks

Both CFX-Pre and ICEM can record your steps, but if you don't know where to start those tools will not be very helpfull. You'll also need some scripting to get the mesh back and forward between Pre and ICEM.

As Singer already said, this is not a straighforward thing to do and definitely not something that can be done through here. You really should contact you local ANSYS support team to help you with this.

Cheers,
Bruno

adunne304 August 22, 2013 06:15

Would it not be easier just to use the mesh deformation tool within CFX?

Spring.s August 23, 2013 11:04

Quote:

Originally Posted by brunoc (Post 447203)
Both CFX-Pre and ICEM can record your steps, but if you don't know where to start those tools will not be very helpfull. You'll also need some scripting to get the mesh back and forward between Pre and ICEM.

As Singer already said, this is not a straighforward thing to do and definitely not something that can be done through here. You really should contact you local ANSYS support team to help you with this.

Cheers,
Bruno



Hi brunoc
Thanks for your replay. I do translational movement with ICEM but I can't remesh rotational movement. Via append the commands to already rpl file in Icem may be prepare some sectional of remeshing, isn't it?
Does it need to other scripts?

Best regards

Spring.s August 23, 2013 11:12

Quote:

Originally Posted by adunne304 (Post 447405)
Would it not be easier just to use the mesh deformation tool within CFX?




I need to remesh for this case because that inclusive great mesh deformation.

gwen520 September 24, 2014 09:32

Hello,Spring.s have you solve your problem? I am now modeling a reciprocating compressor, and I also have to get the mesh regenerated. However, Ieven don't know how to handle the translational part,can you give me some help?

Lesson September 30, 2014 05:25

Hi Gwen

Sorry. I didn't understand.
What kind of problem do you have ???
Do you want remesh your geometry? Or Have you problem with movment of the piston?

Thanks
Fely


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