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Estimating velocity fluctuation's component based on Reynolds stress

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Old   August 23, 2014, 06:59
Default Estimating velocity fluctuation's component based on Reynolds stress
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Hi,

Can I estimate the value of velocity fluctuation's component based on Reynolds stress tensor?

For example, if I have a simulation that is:
-steady state (simpleFoam)
-constant density
-turbulence is modeled using LRR RSM

and at the end of this simulation I'd like to estimate the values of velocity fluctuation's components in this way (example for z-direction fluctuation):

Code:
 R_{zz}=\rho\overline{u'_z u'_z}=\rho\overline{(u')^2_z}
so

Code:
 \overline{u'_z}=\frac{\sqrt{R_{zz}}}{\rho}
Is that correct?

Or are in simpleFoam the Reynolds stress tensor components already divided by density? In case of which it is already:

Code:
 \overline{u'_z}=\sqrt{R_{zz}}
Is any of this correct?
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Old   September 12, 2014, 22:19
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Huang Xianbei
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I don't think so. You'd better use u-umean, considering your simulation is steady, it's impossible to estimate the fluctuation (my opinion)
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