I can't be sure as I've never adopted some methods that you are using. 
Once, I heard that a colleague had issues with mapping + homogeneous expansion, after all he ended up using a 3D mesh. He did not use a passive scalar, but his problems were related to the results, I'm not sure what exactly.
Anyway, are you sure about your body force implementation? Are you aware it's being defined for the whole domain and every time step? Perhaps, you should test without the body force and/or for a specific region and not state the same values of w for T. Also, if doable, I suggest trying with a 3D mesh.
Beyond that, I would not know what to suggest, sorry.



Em qui., 2 de jan. de 2025 às 10:33, Antonio Mazzara <ant.mazzara@studenti.unina.it> escreveu:

Hi Daniel,

Thank you very much for your response to my previous message. I greatly appreciate the time you took to provide me with potential solutions.

Unfortunately, I regret to inform you that despite following your suggestions, the issue I originally reported still persists. I tried different combinations of methods and even reduced the timestep.

To assist you in further investigating the problem, I have attached part of my configuration file for your review. I hope it can help identify any potential inconsistencies or errors that might be contributing to the issue.

Please let me know if there’s any additional information I can provide to assist you. I remain at your disposal for further clarification or testing if needed.

Thank you again for your support and patience.

Looking forward to your reply.

Best regards,
Antonio

Il 27/12/2024 18:20, Daniel Garcia ha scritto:
Hello Antonio, how are you?

Usually, I get that error when the simulation diverges, so try to monitor the CFL to see if that is the case. If so, evaluate the possibility of reducing the time step. 
However, that could be the option of something wrong with the setup or the combination of methods is not implemented. I'm suspicious about that because the error would be completely different, I guess so...

If you have solved the problem, please answer so it can be registered in the forum.

Att,
Daniel.







Em seg., 23 de dez. de 2024 às 21:36, ANTONIO MAZZARA <ant.mazzara@studenti.unina.it> escreveu:

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Dear all,

When I run a 2.5D simulation with a coordinate transformation and an extra passive scalar transport, I get the following error:
      
      CG iterations made = 5001 using tolerance of 1e-09 (error = -nan, rhs_mag = 1)
      Fatal   : Level 0 assertion violation
      Exceeded maximum number of iterations

However, if I repeat the simulation without the passive scalar transport, it proceeds correctly.
Has anyone else encountered the same problem? If so, would you be able to assist me in resolving it?
Thank you in advance for youe help,

Antonio.
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