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Why the results change from time to time
Posted 24 feb 2011, 05:55 GMT-5 Low-Frequency Electromagnetics, RF & Microwave Engineering, Mesh, Results & Visualization, Studies & Solvers 2 Replies
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I got a problem in using the COMSOL.
My task is to calculate the impedance between two contacts/conductors which are laid in a multi-layered(about 12) substrate under different frequence.
I choose the AC/DC Module-Quasi-Static,Electric-Electric Currents. I also set the " Weak constraints" as "on".
I tried different levels of mesh and different Input propertes for the port from Forced voltage to Fixed current and Fixed current density. But I can NOT get a stable solution. It changed when I recalculate it.
And I have no idea about how to choose the solver.
Due to I need the result of different frequence, I choose the "Parametric". And I use the "Direct (SPOOLES)" . I also tried the GMRES but it showed me a message" The diagonal have zero" or "Can't calculate the complex..."
The biggest problem is the unstable result. It chages every time!
Anyone has any idea for me?
Any comment will be gratulated, no matter about the right "Module" , the "Input propertes" , the "Mesh"(I only use free mesh) or the "Solver".
Thanks in advance!
My task is to calculate the impedance between two contacts/conductors which are laid in a multi-layered(about 12) substrate under different frequence.
I choose the AC/DC Module-Quasi-Static,Electric-Electric Currents. I also set the " Weak constraints" as "on".
I tried different levels of mesh and different Input propertes for the port from Forced voltage to Fixed current and Fixed current density. But I can NOT get a stable solution. It changed when I recalculate it.
And I have no idea about how to choose the solver.
Due to I need the result of different frequence, I choose the "Parametric". And I use the "Direct (SPOOLES)" . I also tried the GMRES but it showed me a message" The diagonal have zero" or "Can't calculate the complex..."
The biggest problem is the unstable result. It chages every time!
Anyone has any idea for me?
Any comment will be gratulated, no matter about the right "Module" , the "Input propertes" , the "Mesh"(I only use free mesh) or the "Solver".
Thanks in advance!
2 Replies Last Post 4 mar 2011, 01:35 GMT-5
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Posted:
1 decade ago
Anybody help?
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Posted:
1 decade ago
Hi
i believe the easiest for us out here is that you say which version you are running and upload the model or explain it in detail, because that behavior is not really "normal" I agree, but its impossible for us out here to give a reasonable reply, it's to case specific for us to understand, in other words it should not happen if the model is correctly set up, but there are so many fields and selections in COMSOL that it is easy to miss one ;)
--
Good luck
Ivar
i believe the easiest for us out here is that you say which version you are running and upload the model or explain it in detail, because that behavior is not really "normal" I agree, but its impossible for us out here to give a reasonable reply, it's to case specific for us to understand, in other words it should not happen if the model is correctly set up, but there are so many fields and selections in COMSOL that it is easy to miss one ;)
--
Good luck
Ivar