Heat transport scaling and transition in geostrophic rotating convection with varying aspect ratio

Abstract

We present high-precision experimental and numerical studies of the Nusselt number $Nu$ as functions of the Rayleigh number $Ra$ in geostrophic rotating convection with domain aspect ratio $\Gamma$ varying from 0.4 to 3.8 and the Ekman number Ek from $2.0\times 10^{-7}$ to $2.7\times 10^{-5}$. The heat-transport data $Nu(Ra)$ reveal a gradual transition from buoyancy-dominated to geostrophic convection at large $Ek$, whereas the transition becomes sharp with decreasing $Ek$. We determine the power-law scaling of $Nu\sim R{a}^{\gamma }$, and show that the boundary flows give rise to pronounced enhancement of $Nu$ in a broad range of the geostrophic regime, leading to reduction of the scaling exponent $\gamma$ in small $\Gamma$ cells. The present work provides new insight into the heat-transport scaling in geostrophic convection and may explain the discrepancies observed in previous studies.

arXiv comment5 pages, 4 figures, 1 table

References in corpus (15)

• The unifying theory of scaling in thermal convection: The updated prefactors
• Approaching the Asymptotic Regime of Rapidly Rotating Convection: Boundary Layers vs Interior Dynamics
• Prandtl-, Rayleigh-, and Rossby-number dependence of heat transport in turbulent rotating Rayleigh-Benard convection
• Transitions between turbulent states in rotating Rayleigh-Benard convection
• Heat transport in the geostrophic regime of rotating Rayleigh-B{é}nard convection
• Heat transport in turbulent Rayleigh-Benard convection: Effect of finite top- and bottom-plate conductivity
• A nonlinear model for rotationally constrained convection with Ekman pumping
• Boundary Zonal Flow in Rotating Turbulent Rayleigh-Bénard Convection
• A Heuristic Framework for Next-Generation Models of Geostrophic Convective Turbulence
• Turbulent rotating convection confined in a slender cylinder: the sidewall circulation
• Laboratory Exploration of Heat Transfer Regimes in Rapidly Rotating Turbulent Convection
• Multiple-resolution scheme in finite-volume code for active or passive scalar turbulence
• The sensitivity of rapidly rotating Rayleigh--Bénard convection to Ekman pumping
• Fine vortex structure and flow transition to the geostrophic regime in rotating Rayleigh-Bénard convection
• Enhanced azimuthal rotation of the large-scale flow through stochastic cessations in turbulent rotating convection with large Rossby numbers

Cited by in corpus (8)

• Latitudinal regionalization of rotating spherical shell convection
• Oscillatory thermal-inertial flows in liquid metal rotating convection
• Rotating convective turbulence in moderate to high Prandtl number fluids
• Reynolds number scaling and energy spectra in geostrophic convection
• Robust wall modes and their interplay with bulk turbulence in confined rotating Rayleigh-Bénard convection
• Bridging the Rossby number gap in rapidly rotating thermal convection
• Optimal heat transport in rotating Rayleigh-Bénard convection at large Rayleigh numbers
• Seven decades of exploring planetary interiors with rotating convection experiments