Pair correlation function of vorticity in a coherent vortex
Abstract
We study the correlations of vorticity fluctuations inside a coherent vortex resulting from the inverse energy cascade in two-dimensional turbulence. The presence of a coherent flow, which is a differential rotation, suppresses small-scale fluctuations of the flow, which are created by an external force, and lead to the fact that these fluctuations can be considered as non-interacting and, therefore, examined in a linear approximation. We calculate the pair correlation function of vorticity and demonstrate that it has a power-law behavior both in space and in time. The obtained results allow us to start a systematic study of the effects associated with the nonlinear interaction of fluctuations, which play an essential role on the periphery of a coherent vortex. Our results are also applicable to the statistics of a passive scalar in a strong shear flow.
Cite
@article{arxiv.2403.00501,
title = {Pair correlation function of vorticity in a coherent vortex},
author = {I. V. Kolokolov and V. V. Lebedev and M. M. Tumakova},
journal= {arXiv preprint arXiv:2403.00501},
year = {2024}
}