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Error: Singular matrix

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Hi All,

I have problem i wish you can help me with it; as when i try to module the Maxwell- Stefan equations at the anode and cathode of PEM fuel cell i got this error. please a dvice

Thank you

4 Replies Last Post 18.05.2015, 04:11 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 10.01.2010, 05:15 GMT-5
Hi

you do not give many details there, but singular matrix means mostly that you have not defined enough variables, are you suing material data that need extra variables, have you defined enough boundary conditions ?

Check your geoemtric and dependent variables, and find out if they are sufficiently defined by your boundary conditions, mostly the error would dissapear.

If not try to find an example on the web or in the doc, and start with that one.
Good luck
Ivar
Hi you do not give many details there, but singular matrix means mostly that you have not defined enough variables, are you suing material data that need extra variables, have you defined enough boundary conditions ? Check your geoemtric and dependent variables, and find out if they are sufficiently defined by your boundary conditions, mostly the error would dissapear. If not try to find an example on the web or in the doc, and start with that one. Good luck Ivar

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Posted: 1 decade ago 07.09.2011, 01:33 GMT-4
hello...

i am having the same problem of - SINGULAR MATRIX.
i am trying to simulate a simple flow of a fluid in square tube.
i am using PDE mode, and i have mentioned all required boundary conditions.

pls help.


thanks a lot.
mainak.
hello... i am having the same problem of - SINGULAR MATRIX. i am trying to simulate a simple flow of a fluid in square tube. i am using PDE mode, and i have mentioned all required boundary conditions. pls help. thanks a lot. mainak.


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Posted: 9 years ago 20.04.2015, 08:33 GMT-4
Hi,Ivar
I have some questions about the 3d grating compution. The first, does COMSOL simulate it successlly? So far, I havn't seen any report about it and I failed to get it. The errors like this so. So, if you can, could you give me a model.
Thanks
Good luck.
Robertburns
Hi,Ivar I have some questions about the 3d grating compution. The first, does COMSOL simulate it successlly? So far, I havn't seen any report about it and I failed to get it. The errors like this so. So, if you can, could you give me a model. Thanks Good luck. Robertburns

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Posted: 9 years ago 18.05.2015, 04:11 GMT-4
Hi Ivar,

I am running a simulation where I determine a coil current with the use of global equations. The 2d simulation works but when I want the advance to a 3d simulation I encounter the Singular matrix error. You spoke of insufficient boundary conditions. What kind of boundary conditions am I not taking into account that make the difference between 2d and 3d?

Cheers Tom
Hi Ivar, I am running a simulation where I determine a coil current with the use of global equations. The 2d simulation works but when I want the advance to a 3d simulation I encounter the Singular matrix error. You spoke of insufficient boundary conditions. What kind of boundary conditions am I not taking into account that make the difference between 2d and 3d? Cheers Tom

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