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Roland R November 23, 2011 12:51

Moving coordinate frame
 
Hello,

I would like to rotate my subdomain with deforming mesh. This is OK. But this domain moves in a straight line too. Rotation of the body is based on the original X-Y-Z coordinate frame but of course it should move with the body together.
How can I define moving coord frame?

Regards
Roland

singer1812 November 23, 2011 15:16

This is very easy to do, particularly if you are deforming the whole subdomain (then remeshing isn't necessary). If you use rotation and translation matricies to determine your movement you can combine the translation and rotation into one equation, and it can be as complicated as you wish it to be. If you remesh, you will need to add in a de-rotation (of the rotation at the remesh time) and a de-translation (at the time of the remesh time) matricies prior to the actual rotation and translation.

If you give more details on how you are trying to move your mesh, perhaps I can be more specific in an example.

Roland R November 28, 2011 05:42

Hello Singer,

thanks for your answer, but could you give me more detailed explanation? To tell the truth, I don't understand quite...:confused:
My problem:
I would like to simulate a simple 3D aircraft during a genaral figure looping. In addition strong wind attacks the aircraft body therefore the original circle figure will deform. I would like to analyse this deformed looping with combination of translation and rotation.

Regards;
Roland

Quote:

Originally Posted by singer1812 (Post 333325)
This is very easy to do, particularly if you are deforming the whole subdomain (then remeshing isn't necessary). If you use rotation and translation matricies to determine your movement you can combine the translation and rotation into one equation, and it can be as complicated as you wish it to be. If you remesh, you will need to add in a de-rotation (of the rotation at the remesh time) and a de-translation (at the time of the remesh time) matricies prior to the actual rotation and translation.

If you give more details on how you are trying to move your mesh, perhaps I can be more specific in an example.


singer1812 November 28, 2011 10:59

By figure looping do you mean something like this?

http://upload.wikimedia.org/wikipedi...cuban8.svg.png

And if so, couldnt the translation be taken up via the inlet velocity so that you would only be dealing with pure rotation of the body?


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