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Conductivity as a function of coordinates

Posted Jul 8, 2012, 8:09 a.m. EDT Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2 2 Replies

Gita Khalili
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Hi everyone,
I want to define the conductivity in such a way that it be A along a line and B everywhere else. If I import an image of the line and set conductivity (m + n*im1(x,y)) it works perfectly well. Now, I am looking for a similar performance using a built-in function. For example, if I use analytic function of an1 = x and define conductivity as an1(x), conductivity follows this pattern everywhere not only along a line. So, I tried if(y==x, an1(x), m, n). This method works only if the mesh size be extremely fine.
Any suggestion? I would be grateful if you could advise me.
Thank you,
Gita
2 Replies Last Post Jul 10, 2012, 1:29 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 Jul 10, 2012, 3:42 a.m. EDT
Hi

can you try to sort it out in COMSOl nomenclature way, it would help for us to understand.
First are you in 2D or 3D ?
and when you say a "line" is this along a boundary in 2D = geometrically a line, or a line of a boundary in 3D ?

When you enter a variable (i.e.V) in a BC entry it expects normally a field (V(x,y,z,t)) mapping the selected entities

--
Good luck
Ivar
Hi can you try to sort it out in COMSOl nomenclature way, it would help for us to understand. First are you in 2D or 3D ? and when you say a "line" is this along a boundary in 2D = geometrically a line, or a line of a boundary in 3D ? When you enter a variable (i.e.V) in a BC entry it expects normally a field (V(x,y,z,t)) mapping the selected entities -- Good luck Ivar
Gita Khalili
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Posted: 1 decade ago Jul 10, 2012, 1:29 p.m. EDT
Hi Ivar,

Thank you for your reply.

I am in 3D. It might be easier if you to look at one of COMSOL's examples: hot_circuit.mph. In this example, an image was used to define the thermal conductivity. How can I make this pattern for the thermal conductivity using functions? I do not want to import an image of the patch but define it by a series of functions and then determine the conductivity on the basis of the previously define functions. Does it make sense?

Thank you in advance for your help,
Gita
Hi Ivar, Thank you for your reply. I am in 3D. It might be easier if you to look at one of COMSOL's examples: hot_circuit.mph. In this example, an image was used to define the thermal conductivity. How can I make this pattern for the thermal conductivity using functions? I do not want to import an image of the patch but define it by a series of functions and then determine the conductivity on the basis of the previously define functions. Does it make sense? Thank you in advance for your help, Gita

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