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Pointwise constraints for time derivatives are not supported in Comsol 4
Posted 29 ott 2010, 07:50 GMT-4 Studies & Solvers 0 Replies
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I'm trying to build a FSI model in Comsol 4 without using the predefined FSI functionality. I'm using the solid mechanics and the creeping flow module (time domain). Simulating both side by side (just without the coupling terms) works fine. But as soon as I try to couple the velocity of the mechanical part (more or less a simple beam, see file) to the fluid via inlet BC giving "solid.u_tX" etc. as the BC I get the error mentioned in the subject.
If I turn on weak constraints on the boundaries of question and turn on unidirectional (as suggested here:www.comsol.com/community/forums/general/thread/10418/) I get another error:
"Failed to find consistent initial values.
Matrix has zero on diagonal."
Any ideas how to get rid of these errors?
Help would be highly appreciated.
cheers,
Philipp
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Hello Philipp Rüst
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