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Old   January 24, 2008, 10:54
Default Convergence Problems Internal Flow
Haroon Junaidi
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Hi Guys,

I am using a relizable K-Epsilon model for evaluating the pressure drop through a duct.

The solutions seems to be converging but I have setup a monitor for pressure at the inlet and it keeps fluctuating as much as 30%.

Taking the middle value for pressure in case of fluctuation would be a logical argument, however the fluctuations are random and donot have a pattern.

Would really appreciate if someone can give any pointers.

Best regards

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Old   January 25, 2008, 07:06
Default Re: Convergence Problems Internal Flow
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i am also have duct flow we may can cooperate with this send your mail.

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Old   January 30, 2008, 08:40
Default Re: Convergence Problems Internal Flow
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Are you sure your solution is converged? Are the residual gradients flat and level and have they been for long enough? To be sure, lower the convergence level to say 10^-9 and let the simulation iterate for 5000 iterations. The pressure oscillations may dissapear.

Also, you are using a high Reynolds number turbulence model. Try the standard k-omega model or the k-epsilon RNG. These may give you better results.

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