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reverseflow at pressure outlet boundary

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Old   June 16, 2006, 01:51
Default reverseflow at pressure outlet boundary
  #1
Madhukar Rapaka
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hi

i am simulating a flow in a cylindrical geometry. i have defined the outflow with a pressure outlet boundary. During the simulation in fluent, i am getting a warning, that reverse flow in 23 faces at pressure outlet. I have checked my mesh, and itseems to ba ok(i mean to say that the skew sizes and skew angles, edge ratios of the mesh faces are good...some faces have skew size about 0.91). the residuals are decreasing uniformly. my question here is: will there be any problem in the final results becos of the reverse flow at the outlet.

thanks in advance
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Old   June 18, 2006, 07:01
Default Re: reverseflow at pressure outlet boundary
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Fabrice
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Hi,

No worries about reverse flow at your outlet, just try to enlarge your domain of study to decrease this phenomenon.

Fabrice.
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Old   June 19, 2006, 03:40
Default Re: reverseflow at pressure outlet boundary
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Madhukar Rapaka
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hi Fabrice

firast of alla thanks for the response. i have enlarged the domain as u said and running the fluent simulation with the new geometry. now i am getting a new message:

Turbulent viscosity is limited to viscosity ratio of XXXXXX in XX(say 79) cells. And this number is decreasing as the iterations are going forward. what would be the problem.

thanks in advance

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Old   June 19, 2006, 21:13
Default Re: reverseflow at pressure outlet boundary
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Fabrice
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Hi,

I have never had this error message. I think you should read the Fluent manual about the different models of viscosity....

Cheers,

Fabrice.
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Old   June 29, 2006, 08:05
Default Re: reverseflow at pressure outlet boundary
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kumar
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what type of simulation work are u doing with cylindrical geometry? reverseflow is due to inappropriate outlet boundary conditions.
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