DEGREES OF LOCALITY OF ENERGY-TRANSFER IN THE INERTIAL RANGE

Recent interpretations of direct numerical simulation (DNS) measurements have led some authors to suggest that energy is largely transferred downscale locally, supporting a basic concept of the Kolmogorov phenomenology that leads to the universal inertial subrange. However, these authors conclude that the local energy transfer results from nonlocal triad interactions. This claim brings into question the validity of the assumption of the statistical independence of the large- and small-scale motions in the Kolmogorov universal theory of turbulence. In this Letter, the measured raw transfer interactions have been summed in a way that directly indicates the scale disparity (s) of contributions to the net energy flux across the spectrum. It is found that the dependence upon s closely follows the s-4/3 form predicted by classical arguments. As a result, it is concluded that DNS measurements, in fact, lend support to the classical Kohnogorov phenomenology of local interactions and local transfer in an inertial range.