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magnetic flux integration with magnetic field

Posted Jul 24, 2012, 11:33 a.m. EDT Low-Frequency Electromagnetics 3 Replies

Ceren B
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Hi,

I am trying to do a magnetic flux integration from magnetic field.
I defined a boundary (in 3D geometry) of integration 'boun_flux', then typed the eqn in variables as:

flux = boun_flux(mef.normH)

but I think something's wrong, since the inductance I'm calculating should be 3.36e-10 H. But I'm getting 1.5e-10 H. That is too much as an error percentage, right?

Could you please help me?

3 Replies Last Post Jul 24, 2012, 5:22 p.m. EDT
L. Queval
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Posted: 1 decade ago Jul 24, 2012, 11:57 a.m. EDT
Hi,

It doesnt seem to be such a big error considering you are in the 1e-10 H order. But I am not sure about your
flux = boun_flux(mef.normH). normH is norm of the vector H. But the flux is not the integral of the norm of H over a surface. This is the integral of the component of B normal to the surface over the surface.

--
L. Queval
Hi, It doesnt seem to be such a big error considering you are in the 1e-10 H order. But I am not sure about your flux = boun_flux(mef.normH). normH is norm of the vector H. But the flux is not the integral of the norm of H over a surface. This is the integral of the component of B normal to the surface over the surface. -- L. Queval
Ceren B
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Posted: 1 decade ago Jul 24, 2012, 12:09 p.m. EDT
Mr. Queval,

thank you. Yes I know that the flux is the integral of the component of B normal to the surface over the surface.

My surface is a rectangle in yz plane. So, the normal component of the field to this surface is the x component of the field.
So I typed:

boun_flux(mef.Hx)

However with this, the inductance comes much more smaller: 9e-12 H.

I don't think I did something wrong in the calculation of the current.
I chose a surface again and typed:
boun(mef.normJ)
Since mefJ is current density, it makes sense to integrate like this.
Mr. Queval, thank you. Yes I know that the flux is the integral of the component of B normal to the surface over the surface. My surface is a rectangle in yz plane. So, the normal component of the field to this surface is the x component of the field. So I typed: boun_flux(mef.Hx) However with this, the inductance comes much more smaller: 9e-12 H. I don't think I did something wrong in the calculation of the current. I chose a surface again and typed: boun(mef.normJ) Since mefJ is current density, it makes sense to integrate like this.
Ceren B
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Posted: 1 decade ago Jul 24, 2012, 5:22 p.m. EDT
My geometry is coax. You can see the picture in the attachment.
My geometry is coax. You can see the picture in the attachment.

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