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Please help! (error: Undefined value found)

Posted Dec 19, 2011, 12:09 a.m. EST Battery Design Version 4.2a 5 Replies

Saeid Movahed
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Hello everyone,

I’m working on the following model from Comsol library:

Batteries and fuel cells>>ht_pem.

When I change the geometry to a more complex one, for example using two or three connected channels instead of a single channel, it gives this error:
Undefined value found.

- Detail: Undefined value found in the equation residual vector.
There are 149 degrees of freedom giving NaN/Inf in the vector for the variable mod1.wH2 at coordinates:
(0.00195433,0.0194965,0), (0.00202966,0.0194855,9.01447e-005), (0.0020981,0.0193663,8.8374e-005), (0.00198618,0.0193565,0), (0.00201391,0.0194573,0.000187002), ...

As mentioned above, I use a model from comsol library, then this error cannot be because of BC’s or Initial variables. Changing the geometry cause this error!
Can anybody help me on this?
I appreciate any help.
5 Replies Last Post Dec 4, 2012, 7:36 p.m. EST
COMSOL Moderator

Hello Saeid Movahed

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

Omer Selamet
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Posted: 1 decade ago Feb 28, 2012, 3:43 a.m. EST
Hi Saeid

i am having the similar problem. did you find answer for that.

Thanks
Omer
Hi Saeid i am having the similar problem. did you find answer for that. Thanks Omer
Saeid Movahed
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Posted: 1 decade ago Mar 4, 2012, 9:50 a.m. EST
Hi Omer

Sorry, I could not find the solution for the problem. Actually, I do not know what to do!!

Hi Omer Sorry, I could not find the solution for the problem. Actually, I do not know what to do!!
Wiktor Stenström
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Posted: 1 decade ago Mar 6, 2012, 3:13 a.m. EST
I'm having the same type of "new geometry"-related problem as you have. I have asked for help in the thread linked to below but so far no ideas on what is the problem.

www.comsol.se/community/forums/general/thread/26593/

I've tried clearing the old solutions but that did not change anything. When I did export the new geometry to a new COMSOL file it worked but it would of course be better to have everything in one file.
I'm having the same type of "new geometry"-related problem as you have. I have asked for help in the thread linked to below but so far no ideas on what is the problem. http://www.comsol.se/community/forums/general/thread/26593/ I've tried clearing the old solutions but that did not change anything. When I did export the new geometry to a new COMSOL file it worked but it would of course be better to have everything in one file.
Saeid Movahed
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Posted: 1 decade ago Mar 10, 2012, 5:05 p.m. EST
It is strange, in my model, all the modeling proceses are the same as comsol library model(Batteries and fuel cells>>ht_PEM), and just geometry has been more complex,

I am confused and Ido not know what the problem is!
It is strange, in my model, all the modeling proceses are the same as comsol library model(Batteries and fuel cells>>ht_PEM), and just geometry has been more complex, I am confused and Ido not know what the problem is!
Anant Singh
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Posted: 1 decade ago Dec 4, 2012, 7:36 p.m. EST
Guys I am in the same boat with you all. I just changed the geometry to a long channel with entrance at one of the end's and renamed the file, rest everything was left unchanged from COMSOL's example, I get the same error. Did anyone figure this out ? Could it be the number of iterations that have to changed. I doubt that is the problem as the solver quits almost instantaneously when asked to solve.

I was however able to use a little bit different geometry but I think it was about the same size of the example. It solved completely fine.

Any suggestions ?
Guys I am in the same boat with you all. I just changed the geometry to a long channel with entrance at one of the end's and renamed the file, rest everything was left unchanged from COMSOL's example, I get the same error. Did anyone figure this out ? Could it be the number of iterations that have to changed. I doubt that is the problem as the solver quits almost instantaneously when asked to solve. I was however able to use a little bit different geometry but I think it was about the same size of the example. It solved completely fine. Any suggestions ?

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