The nonequilibrium part of the inertial range in decaying homogeneous turbulence
Abstract
We use two related nonstationarity functions as measures of the degree of scalebyscale nonequilibrium in homogeneous isotropic turbulence. The values of these functions indicate significant nonequilibrium at the upper end of the inertial range. Wind tunnel data confirm Lundgren's prediction that the twopoint separation r where the second and thirdorder structure functions are closest to their Kolmogorov scalings is proportional to the Taylor lengthscale λ, and that both structure functions increasingly distance themselves from their Kolmogorov equilibrium form as r increases away from λ throughout the inertial range. With the upper end of the inertial range in nonequilibrium irrespective of Reynolds number, it is not possible to justify the TaylorKolmogorov turbulence dissipation scaling on the basis of Kolmogorov equilibrium.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 September 2019
 DOI:
 10.1209/02955075/127/64004
 arXiv:
 arXiv:1910.04444
 Bibcode:
 2019EL....12764004O
 Keywords:

 47.27.Ak;
 47.27.Gs;
 47.27.Jv;
 Physics  Fluid Dynamics
 EPrint:
 doi:10.1209/02955075/127/64004