Multi-scale theory of rotating turbulence

Abstract

We consider turbulence induced by an arbitrary forcing and derive turbulence amplitude and turbulent transport coefficients, first by using a quasi-linear theory and then by using a multi-scale renormalisation analysis. With an isotropic forcing, the quasi-linear theory gives that the turbulent transport coefficients, both parallel and perpendicular to the rotation vector, have the asymptotic scaling $\Omega^{-1}$ for rapid rotation (i.e. when the rotation rate $\Omega$ is larger than the inverse of the correlation time of the forcing and the diffusion time), while the renormalisation analysis suggests a weaker dependence on $\Omega$, with $\Omega^{-1/2}$ scaling. The turbulence amplitude is found to scale as $\Omega^0 - \Omega^{-1}$ in the rapid rotation limit depending on the property of the forcing. In the case of an anisotropic forcing, we find that non-diffusive fluxes of angular momentum scale as $\Omega^{-2} - \Omega^{-1}$ for rapid rotation, depending on the temporal correlation of the forcing.