Athermodynamic Alignment in the Two-Dimensional Enstrophy Cascade
Chaotic Dynamics
2007-05-23 v1
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.
Cite
@article{arxiv.nlin/0201043,
title = {Athermodynamic Alignment in the Two-Dimensional Enstrophy Cascade},
author = {Xin Wang and Shiyi Chen and Robert E. Ecke and Gregory L. Eyink},
journal= {arXiv preprint arXiv:nlin/0201043},
year = {2007}
}
Comments
4 pages, 6 figures