Menu

Discussion Forum

New Discussion
Filtra

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Solving nonlinear problem using parameter sweep

Posted 6 mar 2012, 21:38 GMT-5 RF & Microwave Engineering, Studies & Solvers Version 4.0a, Version 4.1, Version 4.2, Version 4.2a 4 Replies

Zhiqi Zhang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi, everyone!

I am struggling to solve some nonlinear optical problem (the material has 3rd-order nonlinear optical response to the electrical-magnetic field) using Comsol RF-frequency domain module. But when the nonlinear become significant enough, the calculation can not converge.
I heard that the problem may be solved by using parameter sweep and adding the nonlinear parameter gradually, but I am not sure the right way to do that, I have set

Study 1 > Solver Configurations > Dependent Variables: Initial Values of Variables Solved For / Not Solved For > Method: Initial Expression, Solution: Solver 1

Is that enough? Under the "Mehtod" tab there is another choice as " Solution" , what's the difference with "Initial Expression"? which one should I choose? Under the "Solution" tab there is also another choice as "Parametric 1", what's the difference then?

Is there any thing else I should do? Does anyone has suggestions about how to correctly solve such nonlinear problem?

Thank you!

Best regards!
Zhiqi
4 Replies Last Post 4 gen 2016, 12:06 GMT-5
Alexander Kuznetsov
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 6 mar 2012, 21:56 GMT-5
If you are using iterative solver, try changing it to direct. For RF-simulations, it helps with convergence in many cases.
If you are using iterative solver, try changing it to direct. For RF-simulations, it helps with convergence in many cases.
Zhiqi Zhang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 7 mar 2012, 04:45 GMT-5
Thank you, I used the default solver.

under Stationary solver --> "Direct" tab, it is "MUMPS" solver,
under Stationary solver --> "Fully coupled" tab, the linear slover is "Direct".

I don't know which one do you mean?
Thank you, I used the default solver. under Stationary solver --> "Direct" tab, it is "MUMPS" solver, under Stationary solver --> "Fully coupled" tab, the linear slover is "Direct". I don't know which one do you mean?
Maurice Sesay
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 13 giu 2012, 22:05 GMT-4
Hi,
How did you use COMSOL to solve the nonlinear response? can you please send me the module file.
Regards,
Maurice
Hi, How did you use COMSOL to solve the nonlinear response? can you please send me the module file. Regards, Maurice
Sriram Guddala
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 4 gen 2016, 12:06 GMT-5
HI Zhang,
I am also having the similar confusions that you have faced during nonlinear problem solving. If you have any progress, plese could you share your file. Especially for parametric sweep I am not able to figure out the way to call the intial parameter.

Thanks in advance for the files.

sriram
HI Zhang, I am also having the similar confusions that you have faced during nonlinear problem solving. If you have any progress, plese could you share your file. Especially for parametric sweep I am not able to figure out the way to call the intial parameter. Thanks in advance for the files. sriram

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content