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2D Axisymmetric Helmholtz Coil with Infinite Element Domains

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Hi Folks,

I have used infinite element domains extensively in 3D models with no issue. I have a 2D Axisymmetric simulation I wish to run, simulating the field from a Helmholtz coil.
The model solves fine without infinnite element domains, but when I add the infinite element layer to the problem, I get an incorrect result. I seem to recall an additional boundary condition needs to be added to the model in 2D axisymmetric in order to get correct results with infinite elements, but cannot recall which one. I have attached the model.

Any pointers greatly appreciated!

Mark

p.s. the attached model has the infinite elements added in and you can see the incorrect result. It is simple enough to remove the infinite elements, re-solve and see the correct result.


2 Replies Last Post 02.11.2015, 02:15 GMT-5
Nirmal Paudel COMSOL Employee

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Posted: 9 years ago 30.10.2015, 11:16 GMT-4
Hi,

In 2D-axisymmetry models where you have an Infinite Element Domains, you would need to remove the Infinite Element Domains in the visualization of results. This is due to the singularity in the r=0 axis in the Infinite Element Domain in 2D-axisymmetry models. The computed results in the modeling domain are still correct, but due to this numerical artifact, it is suggested to just visualize the results in the domains other than IED. In your model, right click on "Results -> Data Sets -> Study 1/Solution1" and add "Selection". In the selection sub-node, add only 2, 4 and 5 (NOT 1 & 3).

Best Regards,
Nirmal
Hi, In 2D-axisymmetry models where you have an Infinite Element Domains, you would need to remove the Infinite Element Domains in the visualization of results. This is due to the singularity in the r=0 axis in the Infinite Element Domain in 2D-axisymmetry models. The computed results in the modeling domain are still correct, but due to this numerical artifact, it is suggested to just visualize the results in the domains other than IED. In your model, right click on "Results -> Data Sets -> Study 1/Solution1" and add "Selection". In the selection sub-node, add only 2, 4 and 5 (NOT 1 & 3). Best Regards, Nirmal

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Posted: 9 years ago 02.11.2015, 02:15 GMT-5
Hi Nirmal,

That works great, thanks for the assistance!

Regards,

Mark
Hi Nirmal, That works great, thanks for the assistance! Regards, Mark

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