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arXiv · 2403.00501

Pair correlation function of vorticity in a coherent vortex

I. V. Kolokolov·V. V. Lebedev·M. M. Tumakova
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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.

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I. V. Kolokolov, V. V. Lebedev, M. M. Tumakova. 2024-03-01. Pair correlation function of vorticity in a coherent vortex. https://doi.org/10.1134/s0021364022603116

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