The Viscous Lengths in Hydrodynamic Turbulence are Anomalous Scaling Functions

Abstract

It is shown that the idea that scaling behavior in turbulence is limited by one outer length $L$ and one inner length $η$ is untenable. Every n'th order correlation function of velocity differences $\bbox{\cal F}_n(\B.R_1,\B.R_2,\dots)$ exhibits its own cross-over length $η_{n}$ to dissipative behavior as a function of, say, $R_1$. This length depends on $n$ {and on the remaining separations} $R_2,R_3,\dots$. One result of this Letter is that when all these separations are of the same order $R$ this length scales like $η_n(R)\sim η(R/L)^{x_n}$ with $x_n=(ζ_n-ζ_{n+1}+ζ_3-ζ_2)/(2-ζ_2)$, with $ζ_n$ being the scaling exponent of the $n$'th order structure function. We derive a class of scaling relations including the ``bridge relation" for the scaling exponent of dissipation fluctuations $μ=2-ζ_6$.