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arXiv · 1801.00493

Generation of large-scale vorticity in rotating stratified turbulence with inhomogeneous helicity: mean-field theory

N. Kleeorin·I. Rogachevskii
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Abstract

We discuss a mean-field theory of generation of large-scale vorticity in a rotating density stratified developed turbulence with inhomogeneous kinetic helicity. We show that the large-scale nonuniform flow is produced due to ether a combined action of a density stratified rotating turbulence and uniform kinetic helicity or a combined effect of a rotating incompressible turbulence and inhomogeneous kinetic helicity. These effects result in the formation of a large-scale shear, and in turn its interaction with the small-scale turbulence causes an excitation of the large-scale instability (known as a vorticity dynamo) due to a combined effect of the large-scale shear and Reynolds stress-induced generation of the mean vorticity. The latter is due to the effect of large-scale shear on the Reynolds stress. A fast rotation suppresses this large-scale instability.

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N. Kleeorin, I. Rogachevskii. 2018-01-01. Generation of large-scale vorticity in rotating stratified turbulence with inhomogeneous helicity: mean-field theory. https://doi.org/10.1017/s0022377818000417

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