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Permanent magnet falling in a tube

Posted Mar 6, 2012, 6:24 a.m. EST Low-Frequency Electromagnetics, Results & Visualization, Structural Mechanics Version 4.2a 3 Replies

Shoval Zoran
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Hi everybody,

In one of my tests I wanted to see if COMSOL takes care and computes the eddy currents, or if I should make it compute them. (if you have an immidiate answer, I'll be glad, by the way :) ) So I wanted to create the simplest test model I could find - and the first one I thought of was a magnet falling in a tube by gravity. In case I'm not clear - www.youtube.com/watch?v=kU6NSh7hr7Q around 1:45 is the model I'm talking about.

Anyway - I constructed the model in an axisymmetric 2D. Geometry is easy and fine, but I'm having trouble with the rest. I inserted both Structural mechanics and Magnetism - one to make it fall, and the other to study our goal. The model solved, but from the results I am seeing I'm not comfortable enough with it. I'm not sure it is correct, and in no way can I actually see the displacement of the magnet through time. It always seems to show me the displacement *field*, which I'm not sure what it is(I'm not a native English speaker).

Can you review the model and see?

Thank you for your time,

Shoval.
3 Replies Last Post Mar 11, 2012, 7:00 a.m. EDT
Edgar Kaiser
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Posted: 1 decade ago Mar 6, 2012, 7:09 a.m. EST
Hi

I can tell you that COMSOL does calculate eddy currents in the AC and RF application modules.

Cheers
Edgar
Hi I can tell you that COMSOL does calculate eddy currents in the AC and RF application modules. Cheers Edgar
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 9, 2012, 2:02 a.m. EST
Hi

If you read French (well math is universal ;) you can try this exercice found on google:

iai.heig-vd.ch/fr-ch/Enseignement/Supports/Physique%20%C3%A9lectricit%C3%A9%20et%20magn%C3%A9tisme%20(PHY2)/Aimant_dans_un_tube.pdf

It's part of the training course of a former colleague, now professor at the heigvd

We had some older COMSOL files too somewhere, but I have not amanged to find them back, it's solved rather simply with the latest version in 2D-axi

--
Good luck
Ivar
Hi If you read French (well math is universal ;) you can try this exercice found on google: http://iai.heig-vd.ch/fr-ch/Enseignement/Supports/Physique%20%C3%A9lectricit%C3%A9%20et%20magn%C3%A9tisme%20(PHY2)/Aimant_dans_un_tube.pdf It's part of the training course of a former colleague, now professor at the heigvd We had some older COMSOL files too somewhere, but I have not amanged to find them back, it's solved rather simply with the latest version in 2D-axi -- Good luck Ivar
Shoval Zoran
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Posted: 1 decade ago Mar 11, 2012, 7:00 a.m. EDT
Hi again,

I opened the file but I could not quite understand what it was describing just by reading the equations :( nevermind though; for some reason I cannot attach my attempt at making the model. Is there any chance you can find the model you talked about, or even create a new one(my test model took less than 10 minutes to be fully created from scratch) and attach it here or link me to it?

Thanks for your time Ivar! :)

Shoval~
Hi again, I opened the file but I could not quite understand what it was describing just by reading the equations :( nevermind though; for some reason I cannot attach my attempt at making the model. Is there any chance you can find the model you talked about, or even create a new one(my test model took less than 10 minutes to be fully created from scratch) and attach it here or link me to it? Thanks for your time Ivar! :) Shoval~

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