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Error message while running three physics in COMSOL 4
Posted Feb 4, 2011, 1:04 p.m. EST Studies & Solvers Version 4.0 1 Reply
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Hello,
I get the following error message when I run the attached code in COMSOL 4. I am not sure what is causing it.
Failed to find consistent initial values.
Singular matrix
The model involves three physics, magnetic field no currents, convection diffusion and migration and laminar flow.
Any help will be appreciated.
Asha
I get the following error message when I run the attached code in COMSOL 4. I am not sure what is causing it.
Failed to find consistent initial values.
Singular matrix
The model involves three physics, magnetic field no currents, convection diffusion and migration and laminar flow.
Any help will be appreciated.
Asha
Attachments:
1 Reply Last Post Feb 5, 2011, 10:01 a.m. EST
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Posted:
1 decade ago
Hi
it typically mans tha you do not have neough BC (boundary conditions) or some materialdata/definitions might be missing.
If I understand your model you have 3 physics layers, a magnetic mfnc, a NS flow spf, and a Nerst Planc chnp.
But I do not see complete defined matraisl and BC for all three physics.
Then you intend to solve all 3 in a time stepping way, but I have the impression that the magnetic one is a static case (my guess), if so, you should solve it separately in a stationary way as the MF will not change, and use that as initial conditions for the other two. I would almost guess that you could solve the SPF also in a stationary way as the input velocity is constant, so perhaps it could also be solved separately, then you have only the last case in time series, which will allow for easier and better convergence
It is worth to solve each separately, in any case first to check that each system solves by its own, and then only you mix all three. If you had started like that, then I would bet that you would have already finish your model ;)
--
Good luck
Ivar
it typically mans tha you do not have neough BC (boundary conditions) or some materialdata/definitions might be missing.
If I understand your model you have 3 physics layers, a magnetic mfnc, a NS flow spf, and a Nerst Planc chnp.
But I do not see complete defined matraisl and BC for all three physics.
Then you intend to solve all 3 in a time stepping way, but I have the impression that the magnetic one is a static case (my guess), if so, you should solve it separately in a stationary way as the MF will not change, and use that as initial conditions for the other two. I would almost guess that you could solve the SPF also in a stationary way as the input velocity is constant, so perhaps it could also be solved separately, then you have only the last case in time series, which will allow for easier and better convergence
It is worth to solve each separately, in any case first to check that each system solves by its own, and then only you mix all three. If you had started like that, then I would bet that you would have already finish your model ;)
--
Good luck
Ivar