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Old   December 16, 2009, 14:42
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Mike
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Can anyone explain the mechanisms of turbulence production in terms of the Reynolds Averaged Navier Stokes equations?

Thanks
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Old   December 16, 2009, 17:47
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Glenn Horrocks
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I won't even start on that one. Visit your local university library and get a turbulence textbook.
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Old   December 16, 2009, 19:50
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Joshua Counsil
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^LOL. Glenn's right. There are full courses dedicated to that topic alone.

The absolute very basic definition is that everything is based on an average value plus a fluctuation (e.g. from the Navier-Stokes equations, u becomes u_avg + u', where u' is the fluctuation in u). The average of the fluctuations is zero. When these terms are substituted into the N-S equations and the N-S equations are averaged, the fluctuation averages disappear (since they are zero). You end up with essentially the N-S equations, but replace each value with the average value (e.g. u becomes u_avg). Also, you end up with an extra term since the average of a product is not the product of an average (e.g. (density x u)_avg does not equal density_avg x u_avg).

Anyway, that's just the tip of the iceberg. Follow Glenn's suggestions.
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