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Can a domain be transformed (rotated) in CFX 11 in a transcient simulation?

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Old   December 7, 2009, 12:24
Default Can a domain be transformed (rotated) in CFX 11 in a transcient simulation?
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Dan Burke
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I am currently running CFX-11. I have a moving domain that needs only to be rotated about the rotation axis - not remeshed. Is there any way to set up a rule to do this between time steps?

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Old   December 7, 2009, 18:18
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Glenn Horrocks
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Use a rotating frame of reference. Then you don't need to use the dynamic meshing stuff and your simulation will be much faster.
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Old   December 8, 2009, 07:01
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Roland Rakos
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Originally Posted by ghorrocks View Post
Use a rotating frame of reference. Then you don't need to use the dynamic meshing stuff and your simulation will be much faster.
I agree with you that the rotating frame is simple method and the simulation time is not too long but in my opinion there is some situation where this approach is not exact.
In the rotating domain a tangential velocity component will appear in every cells . For example: there are a wind turbine which rotates very slowly (RPM:1 rev/s). In the case of application of the rotating frame these tangential components can be seen in every cells of the rotating domain but I think that in the reality these components is much smaller between two blades than along the blades.
In short it is not correct approach that every cells are rotating with the turbine...

What do you think about this?
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Old   December 8, 2009, 07:20
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What do you think about this?
Sounds like rubbish to me

For a rotating frame of reference you are simply using a different frame of reference for your velocities, nothing more than that. And for the case you state where the object is rotating but the flow remains mainly on the stationary frame of reference you use the "alternate rotation model" - look it up in the documentation.
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Old   December 8, 2009, 13:32
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Originally Posted by dburke View Post
I am currently running CFX-11. I have a moving domain that needs only to be rotated about the rotation axis - not remeshed. Is there any way to set up a rule to do this between time steps?

Dan
I have a similiar project to be simulated. However, I need this domain, like yours to be rotating, but is magnetically levitated and hence, its positioning is affected by the fluid dynamics surrounding this domain.

What may be the best approach to do this? Use dynamic meshing for the rotation and at the same time define its 6DOF?
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