Dissipation in Turbulent Flows

This article reviews evidence concerning the cornerstone dissipation scaling of turbulence theory: [Formula: see text], with C ϵ =const., ϵ the dissipation rate of turbulent kinetic energy [Formula: see text], and [Formula: see text] an integral length scale characterizing the energy-containing turbulent eddies. This scaling is intimately linked to the Richardson-Kolmogorov equilibrium cascade. Accumulating evidence shows that a significant nonequilibrium region exists in various turbulent flows in which the energy spectrum has Kolmogorov’s −5/3 wave-number scaling over a wide wave-number range, yet C ϵ ∼Re m I /Re n L , with m≈1≈n, Re I a global/inlet Reynolds number, and Re L a local turbulence Reynolds number.