Turbulence

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Turbulence

• 2003.10.27

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X , Y, Z ( Momentum equation )
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Naviers Stokes Equation
Incompressible
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RANS (Reynold Averaging N-S)
Time Averaging
Reynold Stress
Turbulent Modeling
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Boussinesq Hypothesis
Restated N-S for tensor form
Eddy diffusivity
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Dimension / Turbulent Scale
Velocity scale
Length scale
Time scale
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Kolmogorov hypothesis
Major Premise

• When flow motion have sufficiently large Re ,
  turbulent motion much smaller than integral scale
  have statistically isotropic property.

1) If Inertial force is larger than viscous
force, dissipation rate is independent of
kinematic viscosity.
2) Turbulent motion much smaller than integral
scale depends ONLY dissipation rate
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Kolmogorov scale
Length scale
Velocity scale
Time scale
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Kolmogorov scale Re.
Required Grid
Required Time step
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Energy Cascade