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.

5 pages, 4 figures, 1 table

References in corpus (3)

• Approaching the Asymptotic Regime of Rapidly Rotating Convection: Boundary Layers vs Interior Dynamics
• Boundary Zonal Flow in Rotating Turbulent Rayleigh-Bénard Convection
• Turbulent rotating convection confined in a slender cylinder: the sidewall circulation

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