Cascade processes in rapidly rotating turbulence

TL;DR

This paper investigates energy and helicity transfer in rapidly rotating turbulence, proposing an analogue of Fjortoft's theorem, revealing simultaneous inverse energy and direct helicity cascades, supported by simulations and experiments.

Contribution

It introduces an analogue of Fjortoft's theorem for 3D rotating turbulence, demonstrating dual cascades similar to 2D turbulence.

Findings

Inverse cascade of kinetic energy observed

Direct cascade of kinetic helicity confirmed

Consistent with numerical simulations and experiments

Abstract

The process of the kinetic energy and kinetic helicity transfer over the spectrum in an incompressible, rapidly rotating turbulent flow is considered. An analogue of the Fjortoft theorem for 3D rapidly rotating turbulence is proposed. It is shown that, similar to 2D turbulence, there are two cascades simultaneously: the inverse cascade of the kinetic energy and the direct cascade of the kinetic helicity, which in the case of 2D turbulence corresponds to the cascade of enstrophy. The proposed scenario is in agreement with our earlier calculations, some recent numerical simulations, and physical experiment on rotating turbulence.