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How to solve an eigenvalue problem?
Posted 9 sept. 2011, 11:05 UTC−4 Studies & Solvers Version 4.2 1 Reply
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This is my first time to use COMSOL. I want to solve an eigenvalue problem on a geometry : a unit square with a circle inside. I attached file.
div ( ep^(-1)* grad u)=lambda * u
where ep =1 outside the circle and ep=(1-lambda^(-1))^(-1) inside circle ,
u is continuous on the interior boundary (the boundary of circle) , and
n (ep * grad u) |_outside = n (ep* grad u) |_inside on the interior boundary.
on the boundary of the square,
u is periodic on the up and down sides, and is Floquet periodic on the left and right sides, i.e., u(x_left)=u(x_right)*exp^(i*k), k is a specific real number, for example k=1.
My questions are
1) how to set the interior boundary condition?
2) it is a nonlinear eigenvalue problem. I don't know if the software can solve it. Because it always gives me the error message : undefined value found.
3) how to set the Floquet boundary condition?
Sorry for so many problems. But it really bothered me a lot.
I am using 4.2 version. Please check my attachment.
Thanks a lot.
Yue
Attachments:
Hello Yue Chen
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Did you solve the problem of applying floquet boundary condition?
Thanks.