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Integration in COMSOL 2D (axiallly symetrical problems)

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Hallo,

I am working on a model of a spherical resonator modelled as an axially-symetrical object. In my model I would like to calculate the line integral of the magnetic field component that is tangential to the boundary (my boundary is a quarter of a circle or radius r). I need to calculate:

integrate( |Ht|^2 dS ) over my boundary, where |Ht| is the amplitude of the tangential component of the magnetic field.

I will appreciate a lot any hints as to ways to define a proper expression under the Line Integration that would work. What I am using right now is this:

abs( tremw.Hr + tzemw.Hz )^2

My questions:

1) Is this orrect? I am using a benchmark problem that uses this expression and the results are not correct, which makes me look for problems with my integration here. 2) To test the line integration I used an expression "1", which should give me the length of my boundary (for r = 2mm, I should get 2pir / 4 or 3.14159e-3) . Surprisingly, though, the output for this expression is 2.5132E-5, which is a bit confusing.

Any hints as to what I am doing wrong are strongly appreciated. Many thanks in advance

Best regards

Pawel


1 Reply Last Post Jul 25, 2023, 11:32 a.m. EDT

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Posted: 1 year ago Jul 25, 2023, 11:32 a.m. EDT

Hi,

I am replying to myself -- the problem is solved. The 'line integration' function when applied to a boundary in an axially-symmetrical problem actually calculates the surface integral on that boundary, i.e. the integrated function is additionally multiplied by 2pi, if it does not depend on the azimuthal angle.

This is why I kept receiving 2.5132E-5. The result of calculations of integrate( |Ht|^2 dS ) is OK.

Regards

Pawel

Hi, I am replying to myself -- the problem is solved. The 'line integration' function when applied to a boundary in an axially-symmetrical problem actually calculates the surface integral on that boundary, i.e. the integrated function is additionally multiplied by 2pi, if it does not depend on the azimuthal angle. This is why I kept receiving 2.5132E-5. The result of calculations of integrate( |Ht|^2 dS ) is OK. Regards Pawel

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