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First-order global equation gives singular matrix error

Posted 28 ago 2014, 11:38 GMT-4 Version 4.4 0 Replies

Dong Liu
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Hi everyone,

I am using rotating electrical machinery physics in AC/DC module to solve a problem. No matter how simple the model is and even if the model is as simple as a small circle of air, when I add a global equation of first order: T-J*dw/dt=0 in which w is the variable and J and T are constants, the stationary solver gives the following error at the just beginning:

"Failed to find a solution.
Singular matrix.

There are 1 void equations (empty rows in matrix) for the variable mod1.w.
at coordinates: (0,0), ...
and similarly for the degrees of freedom (empty columns in matrix).
Returned solution is not converged. "

I think this might be either an intrinsic problem with COMSOL or a mathematical limitation that I don't know yet. Could anyone help me solve this problem?

Best regards,
Dong
0 Replies Last Post 28 ago 2014, 11:38 GMT-4
COMSOL Moderator

Hello Dong Liu

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