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problem: very high turbulent viscosity ratio

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Old   November 8, 2005, 11:28
Default problem: very high turbulent viscosity ratio
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Christine Sindelar
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Dear FLUENT-expert,

I do an open channel simulation (VOF) downstream a water power plant. The calculated velocity field seems sensible. There is a problem with the turbulent viscosity ratio (TVR) however.

It is very high and is limited by FLUENT automatically to 100.000 in approx. 1.500 out of approx. 100.000 cells. I've read in the user's guide that the TVR should be < 10 in external flows. My results are far from this.

Any ideas why this is so and how to reduce TVR?

Thank you!

Christine
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Old   November 8, 2005, 13:10
Default Re: problem: very high turbulent viscosity ratio
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Ernest Bertrand
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Make sure your turbulent initialization is not k=1 and epsilon=1 but something more sensible.
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Old   November 9, 2005, 08:23
Default Re: problem: very high turbulent viscosity ratio
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Martin
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Hello Christine.

Sometimes this limitation occurs due to bad mesh geometry. So maybe refining/coarsing the mesh will help.

Regards Martin
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