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How to access the exact solution (Mode analysis)

Posted 23 janv. 2014, 07:32 UTC−5 Version 4.2a 2 Replies

Marvin Farrell
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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 janv. 2014, 10:38 UTC−5
Lasse Murtomäki
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Posted: 1 decade ago 24 janv. 2014, 02:14 UTC−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
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Posted: 1 decade ago 29 janv. 2014, 10:38 UTC−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

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