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 The information provided may be out of date.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.

How to access the exact solution (Mode analysis)

Posted 23 gen 2014, 07:32 GMT-5 Version 4.2a 2 Replies

Marvin Farrell
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi everyone,
For mode analysis, by setting the computation domain large enough (i.e. 8 lambda*8 lambda), the obtained results are varied as increasing mesh density, so I am just stuck are there any criteria to judge whether the solution access the exact solution or not? Or can I judge from convergence (for example the convergence value should be smaller than ..)?
Thanks for your assistance.
Regards

2 Replies Last Post 29 gen 2014, 10:38 GMT-5
Lasse Murtomäki
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 24 gen 2014, 02:14 GMT-5

Hi everyone,
For mode analysis, by setting the computation domain large enough (i.e. 8 lambda*8 lambda), the obtained results are varied as increasing mesh density, so I am just stuck are there any criteria to judge whether the solution access the exact solution or not? Or can I judge from convergence (for example the convergence value should be smaller than ..)?
Thanks for your assistance.
Regards


Hi

I have a similar problem in electroanalysis where the diffusion domain is, in principle, semi-infinite. The exact value of the dimensionless limiting current on an ultramicroelectorode is 4, and I have studied a lot the effect of the size of the domain and meshing on the limiting current. I have not found any "rule of thumb" for the minimum required domain size; meshing has a large effect. My strategy has been to simulate first a simple case which has an analytical solution, and when the simulation is accurate enough, change the geometry. There always, however, remains an itch if the result is reasonably accurate. I simply do not know, but that applies to all numerics, if it comforts :)

BR
Lasse
[QUOTE] Hi everyone, For mode analysis, by setting the computation domain large enough (i.e. 8 lambda*8 lambda), the obtained results are varied as increasing mesh density, so I am just stuck are there any criteria to judge whether the solution access the exact solution or not? Or can I judge from convergence (for example the convergence value should be smaller than ..)? Thanks for your assistance. Regards [/QUOTE] Hi I have a similar problem in electroanalysis where the diffusion domain is, in principle, semi-infinite. The exact value of the dimensionless limiting current on an ultramicroelectorode is 4, and I have studied a lot the effect of the size of the domain and meshing on the limiting current. I have not found any "rule of thumb" for the minimum required domain size; meshing has a large effect. My strategy has been to simulate first a simple case which has an analytical solution, and when the simulation is accurate enough, change the geometry. There always, however, remains an itch if the result is reasonably accurate. I simply do not know, but that applies to all numerics, if it comforts :) BR Lasse
Marvin Farrell
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 29 gen 2014, 10:38 GMT-5
Hi Lasse,

Thanks for your reply. I am trying to adopt adaptive mesh refinement strategy. I will update it whatever it works or not.

BR
Hi Lasse, Thanks for your reply. I am trying to adopt adaptive mesh refinement strategy. I will update it whatever it works or not. BR

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