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How to set boundary conditions that involve two boundaries?

Posted Mar 20, 2012, 2:48 p.m. EDT Low-Frequency Electromagnetics Version 4.3 4 Replies

Ray
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There are two boundary conditions in my model:

-q*(gradient u2) = 1.5*(q*u(anode)-q*u5(cathode)-E(cathode))
-q*(gradient u3) = -0.5*(q*u(anode)-q*u5(cathode)-E(cathode))

where anode and cathode are two boundaries in different positions along the Y axis. (anode is at -1.5 cm along axis Y, cathode is at 1.5 cm along axis Y).

Basically I need to use the conditions of two boundaries in the above equations. How can I realize that?

Thank you
4 Replies Last Post Jun 17, 2012, 4:31 p.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 20, 2012, 4:19 p.m. EDT
Hi

I would say cut your boundary in two with a point, line or surface, or add a sign(y)* condition to change for y<0, repectively >0

--
Good luck
Ivar
Hi I would say cut your boundary in two with a point, line or surface, or add a sign(y)* condition to change for y0 -- Good luck Ivar
Ray
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Posted: 1 decade ago Mar 20, 2012, 8:44 p.m. EDT
Sorry I'm quite confused. Could you explain it a little, please?
Cutting the boundary is impossible since they are two different boundaries, one is located at -1.5 cm along axis Y, and the other at 1.5 cm along Y. Thanks, Ivar!
Sorry I'm quite confused. Could you explain it a little, please? Cutting the boundary is impossible since they are two different boundaries, one is located at -1.5 cm along axis Y, and the other at 1.5 cm along Y. Thanks, Ivar!
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 21, 2012, 2:13 a.m. EDT
Hi

my turn to be sorry, as I must have missed your question ;)
It would be easier to understand if you upload a simple model, I'm woundering if the issue is not about the variable / field default notation of COMSOL, that played me many games and a lot of confusion before I got it right

--
Good luck
Ivar
Hi my turn to be sorry, as I must have missed your question ;) It would be easier to understand if you upload a simple model, I'm woundering if the issue is not about the variable / field default notation of COMSOL, that played me many games and a lot of confusion before I got it right -- Good luck Ivar
Aruna Shah
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Posted: 1 decade ago Jun 17, 2012, 4:31 p.m. EDT
Hi,

Iam having problem in setting the boundary condition for the 3d generator.
please help me with this

thank you
Hi, Iam having problem in setting the boundary condition for the 3d generator. please help me with this thank you

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