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To plot voltage along surface of a circle.

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I am very new to comsol and I am using v3.5a.
I have placed a static charge at (0,0) in a circle of radius 1cm centered at 0,0 as well. I have defined the material and the boundary.
I would like to know how do I plot the results for voltage along the surface of the circle.
I am able to plot Voltage along x or y axis alone, but unable to figure out how to cover radial distance. Someone please help.

Thanks in advance,
regards
Sunand

3 Replies Last Post Mar 12, 2012, 9:39 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Mar 10, 2012, 3:46 a.m. EST
Hi

I havent used 3.5 for years now, but ther remain still the equation way, if you cannot select an edge and plot along the edge, the easiest is often to add a few internal boundaries to select and plot against, try something along:

define some variables i.e. r_xy=sqrt(x^2+y^2) and then extract the variable you want to analyse w.r.t r_xy, defined on a boundary

--
Good luck
Ivar
Hi I havent used 3.5 for years now, but ther remain still the equation way, if you cannot select an edge and plot along the edge, the easiest is often to add a few internal boundaries to select and plot against, try something along: define some variables i.e. r_xy=sqrt(x^2+y^2) and then extract the variable you want to analyse w.r.t r_xy, defined on a boundary -- Good luck Ivar

Robert Koslover Certified Consultant

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Posted: 1 decade ago Mar 10, 2012, 6:21 p.m. EST
From the "Postprocessing" menu, select "Cross-Section Plot Parameters," then the "Line/Extrusion" tab. You can now enter the quantity you want plot in the "Expression" field, and the path you want to plot it along in terms of its starting coordinates (x0,y0) and ending coordinates (x1,y1).
From the "Postprocessing" menu, select "Cross-Section Plot Parameters," then the "Line/Extrusion" tab. You can now enter the quantity you want plot in the "Expression" field, and the path you want to plot it along in terms of its starting coordinates (x0,y0) and ending coordinates (x1,y1).

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Posted: 1 decade ago Mar 12, 2012, 9:39 a.m. EDT
Thank you Ivar for you reply, but I did not quite get it . I defined the variable but I did not understand what you meant by ' xtract the variable you want to analyze w.r.t r_xy, defined on a boundary ' . Would I be plotting Voltage vs r_xy ? and if yes then how would I change values of x and y.
I want to plot voltage along the circumference from (1,0) to (0,1) . I hope you understand what I am asking.

Regards
Sunand
Thank you Ivar for you reply, but I did not quite get it . I defined the variable but I did not understand what you meant by ' xtract the variable you want to analyze w.r.t r_xy, defined on a boundary ' . Would I be plotting Voltage vs r_xy ? and if yes then how would I change values of x and y. I want to plot voltage along the circumference from (1,0) to (0,1) . I hope you understand what I am asking. Regards Sunand

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