Thermal convection in compressible gas with spanwise rotation

TL;DR

This paper investigates how compressible gas convection behaves under spanwise rotation, revealing the emergence of drifting modes and the conditions under which flow becomes two-dimensional, with implications for laboratory experiments.

Contribution

It introduces numerical simulations of compressible gas convection with spanwise rotation, highlighting the drift at convection onset and the transition to 2D flow, challenging the applicability of the anelastic approximation.

Findings

Drifting mode appears at convection onset due to compressibility and rotation.

Spanwise rotation enforces two-dimensional flow at high Rayleigh numbers.

The anelastic approximation fails under typical experimental parameters.

Abstract

We simulate numerically convection in a rectangular cell filled with an ideal gas rotating about an axis perpendicular to the direction of gravity. This configuration corresponds to an experiment with a convection cell placed in a rapidly rotating centrifuge in which the centrifugal force plays the role of gravity. The compressibility of the gas in combination with the rotation of the cell leads to a drifting mode at the onset of convection. The drift persists despite the presence of sidewalls and is rapid enough to cause the anelastic approximation to fail at parameters typical of realizable laboratory experiments. The global spanwise rotation forces the flow to be 2D unless the Rayleigh number is sufficiently large. The main properties of compressible convection in 2D and 3D are compared.