Athermodynamic Alignment in the Two-Dimensional Enstrophy Cascade

2002/01/22 by Xin Wang, Wang, Xin, Shiyi Chen +5
Physics and Astronomy · #Chaotic Dynamics (nlin.CD) #FOS: Physical sciences #nlin.CD

paper · pdf · doi:10.48550/arxiv.nlin/0201043

4 pages, 6 figures

arxiv created 2002/01/22 · arxiv updated 2009/11/30

Abstract

We study inertial-range statistics in the direct enstrophy cascade of two-dimensional turbulence via a numerical simulation of the forced Navier-Stokes equation. In particular, we obtain the distribution of the enstrophy flux and of the angle of alignment of the large-scale vorticity gradient with the small-scale vorticity transport vector. These distributions are surprisingly symmetrical and ``athermodynamic'', not explainable by a local eddy-viscosity approximation with coefficient of either positive or negative sign. By a systematic evaluation of the role of various triadic interactions, we can trace the origin of the strong symmetry to the dominance of infrared non-local triads in the enstrophy cascade.

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