Generalised Quasilinear Approximation of the Interaction of Convection and Mean Flows in a Thermal Annulus

TL;DR

This paper demonstrates that the Generalised Quasilinear Approximation (GQL) more accurately models the complex interactions of convection, rotation, and mean flows in a thermal annulus than the traditional Quasilinear Approximation, aiding geophysical and astrophysical flow theories.

Contribution

The study shows that GQL significantly improves the approximation of nonlinear dynamics in a thermal annulus compared to QL, enhancing modeling of geophysical and astrophysical flows.

Findings

GQL outperforms QL in modeling convection-rotation interactions.

GQL captures mean flow effects more accurately.

Improved approximation aids statistical theories of geophysical flows.

Abstract

In this paper we examine the interaction of convection, rotation and mean flows in a thermal annulus. In this system mean flows are driven by correlations induced by rotation leading to non-trivial Reynolds stresses. The mean flows act back on the convective turbulence acting as a barrier to transport. For this system we demonstrate that the Generalised Quasilinear Approximation (GQL) (Marston et al 2016) may provide a much better approximation to the complicated full nonlinear dynamics than the widely used Quasilinear Approximation (QL). This result will enable the construction of more accurate statistical theories for the description of geophysical and astrophysical flows.