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Old   June 19, 2017, 09:33
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Hmm... You are in a peculiar predicament here.

So just to be clear: you have a converged solution (residuals, monitors, maybe even animations point out in this direction) and you do not change any boundary conditions, models or URFs but saving files makes things go haywire?

Could you post some screen shots of your residuals and monitors here? There is probably something we have missed. What are your URFs? Is your mesh quality suitable for the task? Have you had an animation of flow field of your calculation? Maybe you are simply in a point of calculation where the next iteration simply gives a different result.
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Old   June 19, 2017, 09:46
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Quote:
Originally Posted by divergence View Post
Hmm... You are in a peculiar predicament here.

So just to be clear: you have a converged solution (residuals, monitors, maybe even animations point out in this direction) and you do not change any boundary conditions, models or URFs but saving files makes things go haywire?

Could you post some screen shots of your residuals and monitors here? There is probably something we have missed. What are your URFs? Is your mesh quality suitable for the task? Have you had an animation of flow field of your calculation? Maybe you are simply in a point of calculation where the next iteration simply gives a different result.
The mass imbalance only change after doing more iterations

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Old   June 19, 2017, 15:35
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Originally Posted by BlackHeartInertia View Post
The mass imbalance only change after doing more iterations

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20170619_142842.jpeg

I attached and image. I couldnt before because I wasnt near my computer. I hope never have that problem you said because that would be fatal. Thats another simulation with a lower temperature. Now Im still iteraring so I will see soon the new result for fluxes imbalances.

Ps. Good nick by the way
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Old   June 20, 2017, 02:27
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Thanks for the pic. The calculation seems to be quite stable also in my opinion simply by evaluating the couple curves presented in the picture. Maybe you could try to lower the flow Courant number to 20 and the explicit relaxation factors for both momentum and pressure to 0.25. These default values usually -at least in my experience- have caused some instabilities in calculations. This depends naturally of the case itself.

Additionally, you might want to update your Fluent to a more modern version at some point Fluent has become much more robust after R14 version.

Oh, one more thing: I assume that the case where you took that screen shot had same kind of trouble with the saving and the mass balance. And I suppose that the current case has the same operational parameters.

Last edited by divergence; June 20, 2017 at 02:45. Reason: additional assumptions
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Old   June 20, 2017, 10:57
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Quote:
Originally Posted by divergence View Post
Thanks for the pic. The calculation seems to be quite stable also in my opinion simply by evaluating the couple curves presented in the picture. Maybe you could try to lower the flow Courant number to 20 and the explicit relaxation factors for both momentum and pressure to 0.25. These default values usually -at least in my experience- have caused some instabilities in calculations. This depends naturally of the case itself.

Additionally, you might want to update your Fluent to a more modern version at some point Fluent has become much more robust after R14 version.

Oh, one more thing: I assume that the case where you took that screen shot had same kind of trouble with the saving and the mass balance. And I suppose that the current case has the same operational parameters.
Thank you very much for your comments helps a lot. I will take your advices and see what happend
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Old   June 26, 2018, 12:05
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Hi all,
I have a mesh of size 8 million. It converges the solution at 90 iterations. Energy, x, y, and z goes down to e-07, k and omega to e-05. My result in focus is CD and CL. The tolerance is changed for the latter two report def from e-03 to e-06. Still it converges at 90. LOL?
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Old   January 21, 2019, 11:12
Default Apdl problem
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Hello
I simulate a cylinder in ansys apdl
I have this error
solution not converged at time ansys apdl
Please help me
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