When reading about turbulent flows and turbulence spectrum I frequently come across the terms 'wavelength' 'wavenumber'. I understand that the energy is transferred from larger eddies to smaller ones and so there is a spectrum of different sized eddies spinning at different velocities. But what does the wavelength and frequency of turbulence mean? Is wavelength the diameter of the various sized eddies? Does the frequency of turbulence mean the angular velocity of vortices or the frequency of variation of different state variables?
I have a feeling that the wavelength is related to some characteristic length of the eddies but why term this 'length' the 'wavelength'? How is it related to waves?