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MRF: how to validate of to know if things were set up correctly?

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Old   March 27, 2012, 15:25
Default MRF: how to validate of to know if things were set up correctly?
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Hi all;
I'm simulating a spinning wheel with MRFSimpleFoam…
How would you check if my setup was correct?
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Old   August 11, 2012, 21:34
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the easy way to validate is to find same study and after compare them...

this is the acadamic way to validate...
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Old   December 14, 2012, 09:21
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Hi Lovecraft22,
I am doing simulation of fan, I want to check case setup.
I want to conform my MRFZone file, I am bit confused.
the axis of rotation is (0 0 1),
origin (0 0 0 ) // how can we conform it?
omega 78.54 // is it should be - or +, for + setting I am not at all getting result.
for - RPM the result deviates 40%.

can you please suggest what should i do?

Thanks,
Aadhavan
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Old   December 14, 2012, 14:33
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Hi Aadhavan;
I'm not sure I actually understood your question.

Btw, you need to specify:
1. your axis direction, for instance (0 0 1) if you want your axis direction to be aligned with the z-direction (meaning you body will rotate along this direction)
2. you axis origin, meaning the point your body will be rotating around, for instance (1 1 0), meaning that point will be located at those coordinates. Of course, if your axis direction is (0 0 1) then you can set whatever you want for the origin z coordinate as it will not matter.
3. omega, is the angular velocity at which your body rotates. It is chosen according the the right hand rule: point your thumb in the same direction as the axis and then your fingers will give you the positive direction for the velocity.

Hope this helps
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Old   December 17, 2012, 05:46
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Hi Lovecraft22,
Thanks for your reply, it seems that my settings are correct, but I dont know what factor is blocking the fan static pressure raise. I am getting only 40Pa static pressure raise but it should be 200Pa. I spend more than 2 months for this issue, still I am not able to figure out the problem.

Thanks,
Aadhavan

Last edited by Aadhavan; December 18, 2012 at 04:27.
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Old   December 17, 2012, 15:11
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It can be due to a large number of things, one could be the mesh on the fan (and on the surrounding region) for instance.
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Old   January 2, 2013, 23:44
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Hi, lovecraft22, what is the dimension of omega? [rad/s] or [rpm]?
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Old   January 3, 2013, 03:55
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Usually it should be rad/s otherwise you can change its units to be whatever you like.
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Old   January 11, 2013, 18:38
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I use paraview to check if my MRF zone is set up properly. Just display the velocity vectors of the rotating walls. So you can check direction and magnitute of the rotational velocity easily.
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Old   January 11, 2013, 20:21
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Quote:
Originally Posted by lovecraft22 View Post
Usually it should be rad/s otherwise you can change its units to be whatever you like.
Thanks lovecraft22, I have checked this in the development of U eqn in Rotating Frame, it showed that the omega's dimension should be rad/s.
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