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Question about Slover paremeters in COMSOL 4.0a

Posted 2 ago 2010, 04:59 GMT-4 Version 4.2 5 Replies

Kyo Lee
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Hi, everyone

In COMSOL 3.5a, There is "Use Hermitian transpose of constraint matrix and in symmetry detection" check box on the Advanced page in the Solver Parameters dialog box. It is excellent for the priodic bondary condition.

But in COMSOL 4, there is not this check box, and then I got the wrong result.


How can figure it out ?

Best wishes.

Kyo

5 Replies Last Post 25 set 2012, 11:43 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2 ago 2010, 05:17 GMT-4
Hi

very interesting remark, I would suggest to ask directly COMSOL support and to report back to us here

--
Good luck
Ivar
Hi very interesting remark, I would suggest to ask directly COMSOL support and to report back to us here -- Good luck Ivar
Magnus Olsson COMSOL Employee

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Posted: 1 decade ago 2 ago 2010, 07:05 GMT-4
Hi,

In COMSOL 3.5a this solver setting was required for problems with periodic boundary conditions involving a phase shift, that is for Floquet-periodic models.

In COMSOL 4, we implement Floquet-periodic boundary conditions in a slightly different way that does not involve using this special solver setting so it is now obsolete and has been removed. The new implementation also opens up for modeling damped Floquet modes - something that was not possible in version 3.5a.

If you are getting incorrect results, I recommend you to contact support so they can have a look at it.

Best regards,

Magnus Olsson,
COMSOL
Hi, In COMSOL 3.5a this solver setting was required for problems with periodic boundary conditions involving a phase shift, that is for Floquet-periodic models. In COMSOL 4, we implement Floquet-periodic boundary conditions in a slightly different way that does not involve using this special solver setting so it is now obsolete and has been removed. The new implementation also opens up for modeling damped Floquet modes - something that was not possible in version 3.5a. If you are getting incorrect results, I recommend you to contact support so they can have a look at it. Best regards, Magnus Olsson, COMSOL
Kyo Lee
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Posted: 1 decade ago 2 ago 2010, 08:47 GMT-4
Thanks for your reply.

I also want to konw how to achieve the periodic boundary condition with phase shift in COMSOL 4.0a.

I opened the old model built by COMSOL 3.5a?I found that the model coupling->liner excrusion be used, and pointwise constraint also be uesd. for example, in source expression like u, and the destination expression like u*exp(i*kx*x).
the result is incorrect. but when the destination expression like U*exp(i*2*pi) = u, the result became right.

best wishes?
Thanks for your reply. I also want to konw how to achieve the periodic boundary condition with phase shift in COMSOL 4.0a. I opened the old model built by COMSOL 3.5a?I found that the model coupling->liner excrusion be used, and pointwise constraint also be uesd. for example, in source expression like u, and the destination expression like u*exp(i*kx*x). the result is incorrect. but when the destination expression like U*exp(i*2*pi) = u, the result became right. best wishes?
Fusheng Ma
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Posted: 1 decade ago 12 lug 2011, 10:06 GMT-4
hi, do you figure it out how to set floquet boundary condition in comsol4.0a? i also have the same problem. thanks.
hi, do you figure it out how to set floquet boundary condition in comsol4.0a? i also have the same problem. thanks.
Tran Quang Dat
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Posted: 1 decade ago 25 set 2012, 11:43 GMT-4

Hi,

In COMSOL 3.5a this solver setting was required for problems with periodic boundary conditions involving a phase shift, that is for Floquet-periodic models.

In COMSOL 4, we implement Floquet-periodic boundary conditions in a slightly different way that does not involve using this special solver setting so it is now obsolete and has been removed. The new implementation also opens up for modeling damped Floquet modes - something that was not possible in version 3.5a.

If you are getting incorrect results, I recommend you to contact support so they can have a look at it.

Best regards,

Magnus Olsson,
COMSOL


Dear Mr Magnus Olsson,

I am using acoustics module in COMSOL 4.2. How can I use Floquet-periodic boundary conditions in Acoustics Module, could you please guide to me?

Thank you very much and look forward to your reply.

Quang Dat
[QUOTE] Hi, In COMSOL 3.5a this solver setting was required for problems with periodic boundary conditions involving a phase shift, that is for Floquet-periodic models. In COMSOL 4, we implement Floquet-periodic boundary conditions in a slightly different way that does not involve using this special solver setting so it is now obsolete and has been removed. The new implementation also opens up for modeling damped Floquet modes - something that was not possible in version 3.5a. If you are getting incorrect results, I recommend you to contact support so they can have a look at it. Best regards, Magnus Olsson, COMSOL [/QUOTE] Dear Mr Magnus Olsson, I am using acoustics module in COMSOL 4.2. How can I use Floquet-periodic boundary conditions in Acoustics Module, could you please guide to me? Thank you very much and look forward to your reply. Quang Dat

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