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Identity pairs, special constraints and partwise continous functions

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Hi All,
I am trying to solve for a part-wise continuous electric potential using the PDE interface.
The reason my potential is partwise is that the the governing equation is

div(c(x,y)*grad(phi(x,y) )=0

The function c(x,y) is a known and defined function that has jumps as it moves from one domain to the other.
I am using standard BC of a grounded edge on one side, a known electrical current density on the other side and no fluxes on the remaining outer boundaries.
However for the two internal boundaries I would like to use a special BC- this is the continuation of the electrochemical potential : log(c)+phi =const.

To this end I have constructed my geometry using assembly (versus the standard union).
I have tried using the Constraint BC from the Pair option.
However I am not receiving the expected result.
Since c is partwise I expect phi to be partwise but I am getting a continuous rise on one side and additional unexpected behavior on the other side.
In the Result section I have added the expected result when the applied current is zero and the result I am getting. Obviously, the result is different.
Any ideas? I have tried using bi-directional and unidirectional BCs as well.

Thanks Yoav


0 Replies Last Post 28.07.2014, 08:18 GMT-4
COMSOL Moderator

Hello Yoav Green

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