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Failed to find consistant initial values. in Electric Current simulation
Posted 10.04.2011, 22:33 GMT-4 Low-Frequency Electromagnetics Version 4.0a, Version 4.2 5 Replies
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Hello Everyone~
I have question and need your help.
In the file I attached, there is simple model comprised of materials, Air, Liver tissue, Blood, Electrodes and Troca base.
When I define block1, 2 and 3 as the material property of Liver tissue, the simulation operates well.
However, if I change the material property, (block1 to blood and block2 to air)
The simulation is stopped at initial step and following message appears in error stem of Time-Dependent Solver 1.
"Failed to find consistent initial values.
Segregated group X1
Singular matrix.
There are 2169 void equations (empty rows in matrix) for the variable mod1.V
at coordinates: (0,0.0239887,0.0605475), (0.000422692,0.0237896,0.0607071), (0.000417261,0.0241921,0.0608184), (0.000343571,0.0239178,0.0603889), (0,0.025,0.06115), ...
and similarly for the degrees of freedom (empty columns in matrix)"
I tried to fix the problem many times, but i couldn't resolve the problem.
In my opinion, the problem is in Electric Current interface because if I enable heat transfer interface only, the simulation operates well.
Can you tell me how to solve this problem or what is the wrong?
Thank you for reading~:)
I have question and need your help.
In the file I attached, there is simple model comprised of materials, Air, Liver tissue, Blood, Electrodes and Troca base.
When I define block1, 2 and 3 as the material property of Liver tissue, the simulation operates well.
However, if I change the material property, (block1 to blood and block2 to air)
The simulation is stopped at initial step and following message appears in error stem of Time-Dependent Solver 1.
"Failed to find consistent initial values.
Segregated group X1
Singular matrix.
There are 2169 void equations (empty rows in matrix) for the variable mod1.V
at coordinates: (0,0.0239887,0.0605475), (0.000422692,0.0237896,0.0607071), (0.000417261,0.0241921,0.0608184), (0.000343571,0.0239178,0.0603889), (0,0.025,0.06115), ...
and similarly for the degrees of freedom (empty columns in matrix)"
I tried to fix the problem many times, but i couldn't resolve the problem.
In my opinion, the problem is in Electric Current interface because if I enable heat transfer interface only, the simulation operates well.
Can you tell me how to solve this problem or what is the wrong?
Thank you for reading~:)
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5 Replies Last Post 02.06.2013, 23:37 GMT-4
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Posted:
1 decade ago
Hi
when you change the material you might (depending on the physics model) change the need for material parameters, the one of air and a few others there are not defined for all required characteristics of your new model.
Always check the materials once you change the model and before you run your simlation. You will see you are missing the epsilonr of air that is about =1
But that is not the cause of your error message, I believe it's because your BC are not all well defined, You should solve first for EC, then only for HT and then only couple them. I normally run a stationary case per physics first, check that the values are globally as expected, then I switch to transient, then I mix them, often first in stationary, then I switch back to transient again. thing takes time (the only T^3 law I know about) but you get htere often quicker like that
--
Good luck
Ivar
when you change the material you might (depending on the physics model) change the need for material parameters, the one of air and a few others there are not defined for all required characteristics of your new model.
Always check the materials once you change the model and before you run your simlation. You will see you are missing the epsilonr of air that is about =1
But that is not the cause of your error message, I believe it's because your BC are not all well defined, You should solve first for EC, then only for HT and then only couple them. I normally run a stationary case per physics first, check that the values are globally as expected, then I switch to transient, then I mix them, often first in stationary, then I switch back to transient again. thing takes time (the only T^3 law I know about) but you get htere often quicker like that
--
Good luck
Ivar
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Posted:
1 decade ago
Hi,
I am also facing a similar problem and the model is attached.Model comprises of a simple 2 D space comprising of water and oil mixtures being heated by microwaves and coupled with Darcy's flow.
I got the error:
Failed to find consistent initial values.
Segregated group X1
Singular matrix.
There are 1 void equations (empty rows in matrix) for the variable mod1.mh.S1256x
at coordinates: (0,0), ...
and similarly for the degrees of freedom (empty columns in matrix)
I have tried to fix it but do not know the reason hence was unable to resolve. I am carrying out a frequency stationary study with COMSOL 4.0 using RF module.
Many thanks for any of your help.
Cheers!
I am also facing a similar problem and the model is attached.Model comprises of a simple 2 D space comprising of water and oil mixtures being heated by microwaves and coupled with Darcy's flow.
I got the error:
Failed to find consistent initial values.
Segregated group X1
Singular matrix.
There are 1 void equations (empty rows in matrix) for the variable mod1.mh.S1256x
at coordinates: (0,0), ...
and similarly for the degrees of freedom (empty columns in matrix)
I have tried to fix it but do not know the reason hence was unable to resolve. I am carrying out a frequency stationary study with COMSOL 4.0 using RF module.
Many thanks for any of your help.
Cheers!
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Posted:
1 decade ago
Can you explain a bit more on what you mean by BC? How does it supposed to be defined? I have tried to run a brain stimulation using a tripole electrode but when I use the "electric current" study module, I get the same error: "singular matrix ..." I couldnt finf one person who can help me with. Even reviewing the comsol and the available models didnt help. none of the models I could open have ever been running a simulation implementing the current sources. There are many Comsol_defined elements which It is not that clear when you can read to make senses of them. I did go over the dynamic help as well as the PDF but didnt find them that much helpful. Simply a model example which at most let you see how to design a simple geometry and run a mechanical engineering study.
I had already posted my issue here ago but no responses.
I had already posted my issue here ago but no responses.
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Posted:
1 decade ago
Hi
you are solving in EC electric current, but how can the current flow if you set conductivity = 0 in the air ? (try 0.001)
singular matrix means mainly you have missed a BC and COMSOL cannot find an UNIQUE solution
perhaps you wanted the electric field with ES electrostatic and not EC ?
--
Good luck
Ivar
you are solving in EC electric current, but how can the current flow if you set conductivity = 0 in the air ? (try 0.001)
singular matrix means mainly you have missed a BC and COMSOL cannot find an UNIQUE solution
perhaps you wanted the electric field with ES electrostatic and not EC ?
--
Good luck
Ivar
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Posted:
1 decade ago
I am wondering if we can simulate electric current flow in a liquid. Which COMSOL module could we use to simulate the current flow in an ionic solution?
Thanks,
Kapil
Thanks,
Kapil