Logarithmic scaling in the near-dissipation range of turbulence

Abstract

A logarithmic scaling for structure functions, in the form $S_p \sim [\ln (r/η)]^{ζ_p}$, where $η$ is the Kolmogorov dissipation scale and $ζ_p$ are the scaling exponents, is suggested for the statistical description of the near-dissipation range for which classical power-law scaling does not apply. From experimental data at moderate Reynolds numbers, it is shown that the logarithmic scaling, deduced from general considerations for the near-dissipation range, covers almost the entire range of scales (about two decades) of structure functions, for both velocity and passive scalar fields. This new scaling requires two empirical constants, just as the classical scaling does, and can be considered the basis for extended self-similarity.