Large-scale vortices and zonal flows in spherical rotating convection

Lin, Yufeng1; Jackson, Andrew2

2021-02-16

10.1017/jfm.2020.1151

JOURNAL OF FLUID MECHANICS   影响因子和分区

0022-1120

1469-7645

Motivated by understanding the dynamics of stellar and planetary interiors, we have performed a set of direct numerical simulations of Boussinesq convection in a rotating full sphere. The domain is internally heated with fixed temperature and stress-free boundary conditions, but fixed heat flux and no-slip boundary conditions are also briefly considered. We particularly focus on the large-scale coherent structures and the mean zonal flows that can develop in the system. At Prandtl number of unity, as the thermal forcing (measured by the Rayleigh number) is increased above the value for the onset of convection, we find a relaxation oscillation regime, followed by a geostrophic turbulence regime. Beyond this we see for the first time the existence of large-scale coherent vortices that form on the rotation axis. All regime boundaries are well described by critical values of the convective Rossby number , with transitions from oscillatory to geostrophic turbulence, and then to the large-scale vortex regime at values and , respectively. The zonal flow is controlled by the convective Rossby number and changes its direction when the flow transitions from the geostrophic turbulence regime to the large-scale vortex regime. While the non-zonal flow speed and heat transfer can be described by the so-called inertial scaling in the geostrophic turbulence regime, the formation of large-scale vortices appears to reduce both the non-zonal flow speed and the efficiency of convective heat transfer.

geostrophic turbulence rotating flows convection in cavities

SCI ; EI

英语

第一 ; 通讯

European Research Council under the European Union's Horizon 2020 research and innovation programme[833848] ; B-type Strategic Priority Program of the Chinese Academy of Sciences[XDB41000000] ; National Natural Science Foundation of China[41904066] ; pre-research project on Civil Aerospace Technologies of China National Space Administration[D020308]

Mechanics ; Physics

Mechanics ; Physics, Fluids & Plasmas

WOS:000618360400001

CAMBRIDGE UNIV PRESS

20210809945135

Atmospheric turbulence ; Boundary conditions ; Heat flux ; Natural convection ; Prandtl number

Fluid Flow, General:631.1 ; Heat Transfer:641.2

ENGINEERING

Web of Science

1.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China
2.Swiss Fed Inst Technol, Inst Geophys, CH-8092 Zurich, Switzerland

Lin, Yufeng,Jackson, Andrew. Large-scale vortices and zonal flows in spherical rotating convection[J]. JOURNAL OF FLUID MECHANICS,2021,912.

Lin, Yufeng,&Jackson, Andrew.(2021).Large-scale vortices and zonal flows in spherical rotating convection.JOURNAL OF FLUID MECHANICS,912.

Lin, Yufeng,et al."Large-scale vortices and zonal flows in spherical rotating convection".JOURNAL OF FLUID MECHANICS 912(2021).