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how to fix error "NaN or Inf found when solving linear system using SOR"

Posted 2023/05/01 18:18 GMT-4 2 Replies

Affifa Adeeb
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Hi I have attached my model. Here outer coil has AC current at 1000Hz and I want to find induced voltage/current in inner coil. I have tried changing mesh, element size, frequency, even solver and boundary conditions but problem never converges and gives error "Undefined value found. - Detail: NaN or Inf found when solving linear system using SOR". And sometimes, it just went off. I would be much obliged if anyone can see whats wrong in model/problem.

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2 Replies Last Post 2023/05/02 14:50 GMT-4
Robert Koslover Certified Consultant
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Posted: 3 years ago 2023/05/02 12:00 GMT-4
Updated: 3 years ago 2023/05/02 12:01 GMT-4

You are using the Magnetic Fields formalism and that means you need to avoid regions of zero conductivity. The Comsol Help system says: "Note that the frequency and time-domain formulations become ill-posed when approaching the static limit. You can extend the useful frequency range downward by adding a low conductivity." So, assign a small non-zero conductivity to the air in your model and it will help the model to converge. I also suggest you try the GMRES solver instead of BiCGStab.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
You are using the Magnetic Fields formalism and that means you need to avoid regions of zero conductivity. The Comsol Help system says: "Note that the frequency and time-domain formulations become ill-posed when approaching the static limit. You can extend the useful frequency range downward by adding a low conductivity." So, assign a small non-zero conductivity to the air in your model and it will help the model to converge. I also suggest you try the GMRES solver instead of BiCGStab.
Affifa Adeeb
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Posted: 3 years ago 2023/05/02 14:50 GMT-4

You are using the Magnetic Fields formalism and that means you need to avoid regions of zero conductivity. The Comsol Help system says: "Note that the frequency and time-domain formulations become ill-posed when approaching the static limit. You can extend the useful frequency range downward by adding a low conductivity." So, assign a small non-zero conductivity to the air in your model and it will help the model to converge. I also suggest you try the GMRES solver instead of BiCGStab.

Thankyou Robert Is there any detailed documentatation related to this scenario? Adding little conductivity to air. I want to make it more clear.

Regards

>You are using the Magnetic Fields formalism and that means you need to avoid regions of zero conductivity. The Comsol Help system says: "Note that the frequency and time-domain formulations become ill-posed when approaching the static limit. You can extend the useful frequency range downward by adding a low conductivity." So, assign a small non-zero conductivity to the air in your model and it will help the model to converge. I also suggest you try the GMRES solver instead of BiCGStab. Thankyou Robert Is there any detailed documentatation related to this scenario? Adding little conductivity to air. I want to make it more clear. Regards

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