Symmetric Gauss-Seidel error

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sophie Lu
Posts: 5
Joined: Mon Jun 09, 2025 8:40 pm

Symmetric Gauss-Seidel error

Post by sophie Lu »

Hi all,

I am running an atmospheric simulation, but it stops every time when it reaches around 360 time steps (time step is 1s in my case), due to this problem:

Symmetric Gauss-Seidel [Velocity]: divergence after 1 iterations:
initial residual: -nan; current residual: -nan

Symmetric Gauss-Seidel: error (divergence) solving for Velocity

I have changed different Gradient reconstruction type, but all Gauss options have this same error. Do you know how to fix it? I attached my run.log and a picture of the mesh. Thanks for your help!

Sophie
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Yvan Fournier
Posts: 4254
Joined: Mon Feb 20, 2012 3:25 pm

Re: Symmetric Gauss-Seidel error

Post by Yvan Fournier »

Hello,

You could increase the logging and postprocessing frequency to get more info on field values when the code starts preventing backflow at the outlet, and a bit before the divergence occurs. Running with a debug build may also help detect some error categories earlier.

Note that v7.0 is not maintained anymore, so upgrading to a current version is also recommended.

Best regards,

Yvan
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