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3D Electric Field Plotting

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Hello,

Apologies if this is a dumb question but how do i get Comsol to compute the vector electric field around an object held at a specific potential?

I would like to see both vector E and mag[E] and perhaps scalar potential Phi around various 3D geometries in air. I cant seem to compute anything other than scalar electric potential V on the surfaces of my model. I need to see the electric field in the air around my model.

From the forums i get the impression that this is something that Comsol routinely computes so i wonder if i am using the wrong module or something.

Attached is an unsolved model of a very simple steel disk surrounded by a box filled with air with a basic mesh applied.

I realise this is a highly symmetric problem and 3D analysis is probably not required but i wish to move on to investigate much more complex 3D geometries so i want to understand the process in its simplest form first.

I am using 4.0a and the electrostatics module.

Thankyou kindly.
Dominic.


6 Replies Last Post Nov 29, 2010, 12:01 p.m. EST

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Posted: 1 decade ago Nov 29, 2010, 8:47 a.m. EST
Hi Dominic,

have a look at plot group 2. You have to add two plots: One for the vector quantity of E and one for the scalar quantity of the magnitude of E. Suitable plots are a slice for the scalar field and volume arrows for the vector field.

Btw: I changed the physics somewhat, because your model didn't solve. But that doesn't affect how to plot the quantities.

Bye
MV
Hi Dominic, have a look at plot group 2. You have to add two plots: One for the vector quantity of E and one for the scalar quantity of the magnitude of E. Suitable plots are a slice for the scalar field and volume arrows for the vector field. Btw: I changed the physics somewhat, because your model didn't solve. But that doesn't affect how to plot the quantities. Bye MV


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Posted: 1 decade ago Nov 29, 2010, 8:54 a.m. EST
Hi Marco,

Thanks very much for this, great help.

Could you possibly tell me what physics you changed? From looking at it, you disabled the infinite element node and simply set the edges to ground,

Is that all?

Thanks again.
Hi Marco, Thanks very much for this, great help. Could you possibly tell me what physics you changed? From looking at it, you disabled the infinite element node and simply set the edges to ground, Is that all? Thanks again.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Nov 29, 2010, 8:56 a.m. EST
Hi

do you mean to visualise the vector field Ex Ey ?, if so try an arrow plot wither surface or volume (3D) arrows

--
Good luck
Ivar
Hi do you mean to visualise the vector field Ex Ey ?, if so try an arrow plot wither surface or volume (3D) arrows -- Good luck Ivar

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Posted: 1 decade ago Nov 29, 2010, 10:09 a.m. EST

Could you possibly tell me what physics you changed? From looking at it, you disabled the infinite element node and simply set the edges to ground,

Is that all?


Yep, that is all. Mathematically not as exact as the infinite elements, but the solution is accurate enough and the point was to show the suitable plot features.
[QUOTE] Could you possibly tell me what physics you changed? From looking at it, you disabled the infinite element node and simply set the edges to ground, Is that all? [/QUOTE] Yep, that is all. Mathematically not as exact as the infinite elements, but the solution is accurate enough and the point was to show the suitable plot features.

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Posted: 1 decade ago Nov 29, 2010, 11:44 a.m. EST
Hi,
Hi,

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Posted: 1 decade ago Nov 29, 2010, 12:01 p.m. EST
Do you know why the infinte element part isn't solving for my simple model? Are there any extra piece of info i need?

Thanks for all your help, i have gotten going now.
Do you know why the infinte element part isn't solving for my simple model? Are there any extra piece of info i need? Thanks for all your help, i have gotten going now.

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