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Several issues with rotation

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Hello,
I am having difficult getting a model to rotate around a specified point. Is there a way to do this? I am using the ALE meshing scheme to parametrize the rotation but it seems to be rotating the figure around its own center. I have tried getting simple figures such as circles and squares to rotate around the origin but they are instead rotating around their own centers. How can I get them to rotate around a specified point, or at least the origin? Also, when they rotate (I am using R*cos(w*t) and R*sin(w*t) for dx and dy by the way) they are displaced by the radius R that I specify and rotate with that radius. This is clearly correct, but can I get them to rotate about their own axis without being displaced any by any radial component? That is, in polar coordinates, the dR is zero and dOmega is nonzero. Please help!

4 Replies Last Post Jul 14, 2011, 11:55 a.m. EDT

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Posted: 1 decade ago Jul 13, 2011, 4:38 a.m. EDT
Did you already find a solution for your problem?
By the way, could you post your file so people can have a look on it?
Did you already find a solution for your problem? By the way, could you post your file so people can have a look on it?

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Posted: 1 decade ago Jul 13, 2011, 11:57 a.m. EDT
Hi Daniel
I have a laser spot on a circular target that I am trying to rotate around the origin since it takes less memory than rotating the entire target, but I was unable to figure it out. Instead I decided to incorporate the movement into the equation for the heat source, using a combination of heaviside functions to show when and where the heat source is active. I have attached both models. The one using the failed ALE mesh is the Ti target 2. Thank you.
Hi Daniel I have a laser spot on a circular target that I am trying to rotate around the origin since it takes less memory than rotating the entire target, but I was unable to figure it out. Instead I decided to incorporate the movement into the equation for the heat source, using a combination of heaviside functions to show when and where the heat source is active. I have attached both models. The one using the failed ALE mesh is the Ti target 2. Thank you.


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Posted: 1 decade ago Jul 14, 2011, 2:30 a.m. EDT
Sorry, but I have Version 4.2 and could not open your files. I'm not an expert in using moving mesh but sounds to me that the option prescribed mesh velocity should work for you. For instance if you specify an object in the global coordinate system and use vx=-y/t vy=x/t you have a cylindrical rotation. Maybe this will help you. Good luck!
Sorry, but I have Version 4.2 and could not open your files. I'm not an expert in using moving mesh but sounds to me that the option prescribed mesh velocity should work for you. For instance if you specify an object in the global coordinate system and use vx=-y/t vy=x/t you have a cylindrical rotation. Maybe this will help you. Good luck!

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Posted: 1 decade ago Jul 14, 2011, 11:55 a.m. EDT
Thanks very much Daniel! I had been using global coordinates but parametrizing the movement under the mesh displacement option. I'll try mesh velocity, hopefully that works
Thanks very much Daniel! I had been using global coordinates but parametrizing the movement under the mesh displacement option. I'll try mesh velocity, hopefully that works

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