Energy Cascade: Difference between revisions

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In a fully turbulent flow, at high Re, we have large eddies breaking up into smaller ones, and those break up as well until �finally the eddies are so small that they are dissipated by viscosity. Clearly the scale at which dissipation occurs depends on the viscosity. A poem by Lewis Fry Richardson:
In a fully turbulent flow, at high Re, we have large eddies breaking up into smaller ones, and those break up as well until finally the eddies are so small that they are dissipated by viscosity. Clearly the scale at which dissipation occurs depends on the viscosity.
 
 
Big whirls have little whirls,
 
Which feed on their velocity,
 
And little whirls have lesser whirls,
 
and so on to viscosity.
 
 
See Kolmogorov's 5/3 law for the energy in terms of wavenumber in the inertial subrange of wavenumbers before dissipation occurs.

Revision as of 14:51, 1 June 2015

In a fully turbulent flow, at high Re, we have large eddies breaking up into smaller ones, and those break up as well until finally the eddies are so small that they are dissipated by viscosity. Clearly the scale at which dissipation occurs depends on the viscosity.

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