After plotting the velocity power spectra, I need to identify the inertial sub range (as shown in figure). As Kolmogorov's "-5/3 power law" holds good only in inertial sub range. Hence to validate the velocity data It is must to Identify the extent of the inertial sub range.
Hello
Take a look at this reference : " Turbulence spectra " :
https://www.io-warnemuende.de/tl_files/staff/burchard/pdf/Turb_Chap4_WS08.pdf
Best regards
The inertial subrange is the range where turbulence kinetic energy is transferred from larger to smaller scales without loss. It is also the range where no external length scale is imposed on what is otherwise a scale-free (power law) cascade. This means that the Richardson eddies of the cascade must be unaffected by proximity to flow boundaries. These requirements are enough to define the upper- and lower-wavenumber limits to the inertial sub-range.
The upper limit is set by loss to dissipation. The scale length for this is the Kolmogorov microscale length, \eta. A reasonably conservative upper limit for the inertial subrange is \kappa \eta
What follows is a ROM valid for engineering situations...not astrphysics nor geophysics:
upper limit ~ integral length/6
lower limit: ~ 60 lkolmogorov
Best regards, good luck,
Claudio Bruno
Dear K. G. Mcnaughton , at the end, I hope you meant \kappa z > \pi. Isnt it?
Oops! Sorry. I switched from the meteorological (and Townsend's) convention to the one widely used in fluid mechanics.
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