paper

A non-perturbative renormalization group study of the stochastic Navier--Stokes equation

arXiv:1202.4588 · doi:10.1103/PhysRevE.86.016315

Abstract

We study the renormalization group flow of the average action of the stochastic Navier--Stokes equation with power-law forcing. Using Galilean invariance we introduce a non-perturbative approximation adapted to the zero frequency sector of the theory in the parametric range of the Hölder exponent of the forcing where real-space local interactions are relevant. In any spatial dimension , we observe the convergence of the resulting renormalization group flow to a unique fixed point which yields a kinetic energy spectrum scaling in agreement with canonical dimension analysis. Kolmogorov's -5/3 law is, thus, recovered for as also predicted by perturbative renormalization. At variance with the perturbative prediction, the -5/3 law emerges in the presence of a \emph{saturation} in the -dependence of the scaling dimension of the eddy diffusivity at when, according to perturbative renormalization, the velocity field becomes infra-red relevant.

RevTeX, 18 pages, 5 figures. Minor changes and new discussions

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