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Old   September 24, 2009, 06:39
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Iuaniu
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Hi over there,

I am modeling a liquid-gas flow. The convergence criteria is RMS=1e-05.
All RMS go smooth (no oscillations) to the criteria AND BEYOND. All physical quantities of interest goes smooth as well. My question is: Why the simulation doesn't stop when the convergence is meet?

Thx,
Iuaniu
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Old   September 24, 2009, 07:50
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Glenn Horrocks
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Have you also activated imbalances as a convergence criteria? Have you set a minimum number of iterations? There could be many reasons why it proceeds past your residuals criteria.
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Old   September 24, 2009, 09:56
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Quote:
Originally Posted by ghorrocks View Post
Have you also activated imbalances as a convergence criteria? Have you set a minimum number of iterations? There could be many reasons why it proceeds past your residuals criteria.

The Conservation target is 0.01 (the default). I think I have found an answer in the documentation.

"To ensure the global balances are met, you may additionally apply a target imbalance for the conservation equations (i.e., a global balance criterion). In such a case, the solver will only stop before the maximum number of iterations if the residual criteria are met and global balances are also met. The value you specify is the fractional imbalance. The default value is 0.01 (i.e., 1%). "

Thank you for reply,
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Old   September 24, 2009, 20:20
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There you have it. You activated imbalances as a convergence criteria and that had not been achieved, even though your residual had been achieved.
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