# Inertial subrange

From AMS Glossary

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## inertial subrange

An intermediate range of turbulent scales or wavelengths that is smaller than the energy-containing eddies but larger than viscous eddies.

In the inertial subrange, the net energy coming from the energy-containing eddies is in equilibrium with the net energy cascading to smaller eddies where it is dissipated. Thus the slope of the energy spectrum in this range remains constant. Kolmogorov showed that the slope is −5/ 3 based on dimensional arguments, namely,

*S*∝ ε^{2/3}*k*^{−5/3}, for ε representing viscous dissipation rate of turbulence kinetic energy,*k*is wavenumber (inversely proportional to the wavelength), and*S*is spectral energy in a Fourier decomposition of a turbulent signal.*Compare*energy spectrum, spectral gap;*see also*Kolmogorov's similarity hypotheses.