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Interior boundary v4.1

Posted Sep 28, 2011, 12:21 p.m. EDT Version 4.1 3 Replies

Cheng Chen
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Hello folks

I'm using the laminar flow & heat transfer physics in COMSOL 4.1, trying to solve problems such as microchannel flow and convective heat transfer. To simplify the model, I want to change the type of an interior boundary, from solid-fluid interface (wall) to an open boundary (outlet). But I cannot find any option to define or change the interior boundaries.

I understand that physically this boundary is unreasonable. But I noticed that COMSOL 3.5a has the option to change the type or equations of interior boundaries. I wonder if this function is eleminated in version 4s or just works in a different way?

Does anyone have similar experience with version 4.1 on these issues? Really appreciate if someone could help me figure this out.

Thank you.
Cheng
3 Replies Last Post Sep 29, 2011, 11:09 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Sep 28, 2011, 3:00 p.m. EDT
Hi

I have hear that v4 has been deigned to accept less "non physical" BC's, so perhaps you have hit one of these. If so there mustbe another way to express your BC, to make it physical. the results would probably be cleaner too, no ? ;)

--
Good luck
Ivar
Hi I have hear that v4 has been deigned to accept less "non physical" BC's, so perhaps you have hit one of these. If so there mustbe another way to express your BC, to make it physical. the results would probably be cleaner too, no ? ;) -- Good luck Ivar
Cheng Chen
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Posted: 1 decade ago Sep 29, 2011, 11:05 a.m. EDT
Hi Ivar, thanks for your advice. But I didn't get the exact idea of "another way". Do you mean I shall modify the model/geometry to make it physical? Or COMSOL 4 has other methods to modify these "non-physical" boundaries?

Thank you.
Cheng
Hi Ivar, thanks for your advice. But I didn't get the exact idea of "another way". Do you mean I shall modify the model/geometry to make it physical? Or COMSOL 4 has other methods to modify these "non-physical" boundaries? Thank you. Cheng
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Sep 29, 2011, 11:09 a.m. EDT
Hi

I mean you must add the PDEs by hand for the specific boundaries, that is the only way to get around COMSOL physics, if you want to go "non physical".

But I would anyhow advice to rethink over the issue and see if there is not a better, respecting fully the physics way ,of doing things

--
Good luck
Ivar
Hi I mean you must add the PDEs by hand for the specific boundaries, that is the only way to get around COMSOL physics, if you want to go "non physical". But I would anyhow advice to rethink over the issue and see if there is not a better, respecting fully the physics way ,of doing things -- Good luck Ivar

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