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If your physics are axisymmetric, you can expect an excellent match between results obtained with a 2D axisymmetric model and the corresponding full-fledged 3D model. Your models are probably not set up correctly. I recommend you post your .mph files so Discussion Forum users can provide insights.
Best,
Jeff

Hi Jeff,

Thank you very much for your response. Here are my .mph files.

Regards

M

Your 3D geometry is not axisymmetric, nor are your boundary conditions. There could be other differences between your two files, but those two jumped at me.
Best,
Jeff

Thanks, Jeff for your respond. But I am simulating a cylindrical geometry therefore, it is axisymmetric. If If it is not the case should the 2D results match with the 3D results or not?

There is another post in the discussion forum entitled: Differences among 2D and 3D results for electroamgnetic problem. It is not possible to quote here then here is copy of part of it:

October 29, 2010 10:06am UTC in response to Ion Quintana
Re: Differences among 2D and 3D results for electroamgnetic problem

Hi

if you are using MEF in V4.0a and you have a factor "2" between external current induced flux obtained by COMSOL and your analytical calculations then try using "MF" instead. (This applies also to the early 4.1.0.74 for me)

I'm waiting for a reply from the COMSOL developers as I suspect a typo behind there, check the equations. There is something I do not catch, and it took me some time to identify what could be wrong.
It's the same with a sign issue on M or Br defined magnets, but this could also be a convention issue that has been changed

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Good luck
Ivar

October 29, 2010 12:52pm UTC in response to Ivar Kjelberg
Re: Differences among 2D and 3D results for electroamgnetic problem

Hi Ivar,

Of course, I am using V4.0a. I have done both simulation (2Daxi and 3D) in MF and error for Hz is less than %1. ( I had done 2D axisymmetric simulation in MEF and 3D in MF). Great!

However, now I have a new question. For this 2D axisymmetric problem, if I use either MF or MEF, the differences between them is the %50. Why?

What is the difference between MF and MEF?

Thanks in advanced.

Jon

October 29, 2010 3:13pm UTC in response to Ion Quintana
Re: Differences among 2D and 3D results for electroamgnetic problem

Hi

I do not believe MEF is correct, I suspect a typo in the formulas, look at the equations behind ;)

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Good luck
Ivar

Regards

Perhaps you sent the wrong file? Your 3D geometry is not axisymmetric: one part of it is a parallelepiped.
Even if you replaced that block with a cylinder your model would still not be axisymmetric due to the non-axisymmetric boundary conditions.
Jeff

Hi Jeff,
Actually it is a cylindrical geometry. That parallelepiped shape is due to the mesh, since I had to deleted the meshes to send the file. If you please either check the geometry 1 or if you build all meshes you will see the cylindrical geometry.

Thanks

See screenshot of your file. Looks like a block to me, regardless of mesh settings :)
Jeff

Hi Jeff,

Oh I see, sorry, that block is the domain. Actually I am simulating a recessed cylinder ( r= 250 nm). The whole model consists of: a big block as domain and two recessed cylinder. I am interested in the second cylinder and I solving the problem for half it. Please see the zoom in screenshots.

Thanks