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Boundary electromagnetic heat source and convective cooling
Posted 7 set 2011, 07:16 GMT-4 RF & Microwave Engineering, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.3 2 Replies
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I am modelling amicroelectrode array with joule heating module. The structure consists of a glass substrate block, an electrode array (spiral or parallel) on top of the substrate, and a fluid medium which covers the electrodes and top surface of the substrate. Thus, there are 3 domains.
When the model does not include any convective cooling through the top surface of the covering medium, the solution converges and produces expected field and temperature patterns. Of course, I get very high heating (up to 100degC).
When I introduce convective cooling node, a number of errors occur:
" failed to find consistent initial values" - when the new node was added
"Out of memory" - when I refined the mesh
And, returning to "normal" mesh again, a new error:
"Repeated error test failures. May have reached a singularity.
Time : 0.004479106337024356
Undefined value found.
NaN or Inf found when solving linear system using SOR
Last time step is not converged."
With the convective cooling, only one boundary is chosen: the top boundary of the medium. This is then automatically de-selected from the Thermal insulation boundaries, which are automatically set to be all other boundaries of the system.
I suspect I have an inconsistency between Boundary Electromagnetic Heat Source, Thermal Insulation and Convective Cooling boundaries.
However, I seem unable to deselect the boundaries from the current automatic selection for the EM Heat source or Thermal Insulation.
How can I do that? Or, what would be the best way to troubleshoot this? Any tipes or advice will be greatly appreciated.
Many thanks.
Hello Tijana Timotijevic
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I am experiencing a similar problem: I am trying to do an analysis in frequency domain, for a SAW.
The physics is piezoelectric devices.
The error message I get is:
"Undefined value found.
- Detail: NaN or Inf found when solving linear system using SOR."
Anyone knows where the problem might come from and which is the solution?
Best regards,
Catalin B.
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In my case it seems the problem was the fact that I had defined a global variable.
After I deleted it, the simulation worked.
Catalin B.