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Old   December 3, 2011, 00:45
Default doubt in post processing
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murugesan
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Hi,
I have a small question: during iterations I get the warning message "reversed flow in xxxx faces on pressure outlet". The number xxxx goes down with iterations. then the solution converges and there are still about 1000 faces in the outlet with reversed flow. If I continue the iterations the number keeps falling, and probably it will reach zero (no more warnings). What does this mean? Is the solution not really converged when FLUENT says so
(according to the default residuals criteria)? IS the solution converged when finally there are no more faces with reversed flow or when this number stays constant?
thanks
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Old   December 3, 2011, 04:18
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shoeb khan
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Hi
may be i am wrong, but according to me
Many times there is a reverse flow problem at the starting of the simulation.
But as we proceed, the reverse flow problem vanishes and it doesn't comes back after a quite a long spam of iteration then surely i can say that the solution is converged.

Correct me if i am wrong please.

SHK
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Old   December 3, 2011, 07:10
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kamran
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In every turbulent model we have some large eddies which may bring about Reversed Flow.That's something normal.
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Old   December 3, 2011, 13:56
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shoeb khan
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No turbulence models doesn't create reverse flows
it just depend on ur geometries

u can switch on turbulence models when ur solution is converged
hope that will help u

shk
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Old   December 4, 2011, 02:47
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kamran
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Model and geometry are both important.
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Old   December 13, 2011, 03:13
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Hi,

According to my understanding, criterion for solution convergence and reverse flow are two different things.

You can always check your solution is converged OR not by simulating for higher criterion of solution convergence.

You can adjust related parameters in pressure-outlet BC if reverse flow is occurring and it is not desirable!

Mehulkumar
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