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weak constraint inlet problem

Posted Apr 18, 2012, 11:53 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2a 0 Replies

Abbie
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Dear all,

I have a problem with weak constraint in laminar flow, where i constraint the inlet pressure (p_inlet) as average pressure with constraint expression: aveop1(p) - p_inlet (laminar flow>weak constraint). Meanwhile, I implement a velocity function at the same inlet boundary (laminar>inlet).

However I faced the error below:

Failed to find consistent initial values.
Singular matrix.

There are 1 degrees of freedom that do not occur in any equation (empty columns in matrix) for the variable mod1.lm.
at coordinates: (0,0), ...
Last time step is not converged.

May I know what's wrong with my boundary setting and how to solve this error?

Thanks.
0 Replies Last Post Apr 18, 2012, 11:53 p.m. EDT
COMSOL Moderator

Hello Abbie

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