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"Flowers" in COMSOL Multiphysics

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Old   March 30, 2009, 13:42
Question "Flowers" in COMSOL Multiphysics
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Diego Ubeda
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Hello everybody,

I'm new here, I'm a Ph.D student in a Spanish University. I work in fuel cell modelling and use COMSOL Multyphisics. There is an issue that is killing me: I obtain real strange results when solving certain kind of problems. Does anybody know why? Did you ever have something like this? Can anybody help me? Please!!

Thank you very much.
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Old   March 30, 2009, 23:11
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The Spartan
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That's usually artifacts and they are due to a poor grid.
If you can be more specific on your problem....

So try refining the mesh.
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Old   March 31, 2009, 03:49
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Diego Ubeda
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First of all, thank you very much for your help, symkimon.
I suspected it was the mesh which was the "guilty" of this problem. I obtain this results when modelling a serpentine fuel cell. Specifically this artifacts appear only in the electric potential of the conductive media DC application mode I use (and consequently in all the variables related to it). I tried to refine the mesh, as you said, but I always get the message "out of memory" while solving again. I have to use a direct solver (UMFPACK, PARDISO or SPOOLES), otherwise the system doesn't converge. Sometimes SPOOLES lets me have a more refined mesh, but it's still insufficient, as "flowers" keep on appearing.
Are you sure that my problem is due to the mesh? Do you think that if I use a more powerful CPU I will overcome this? I use now an AMD Sempron Processor 3200+ at 1.81 GHz, 3.00 GB RAM.

Thank you very much again for your kindness.
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Old   March 31, 2009, 09:51
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Can you send me the file? I got a monster PC here to give it a go. Is it COMSOL 3.5?
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