Convection in rotating flows with simultaneous imposition of radial and vertical temperature gradients

TL;DR

This study investigates heat transport in a rotating fluid annulus with combined radial and vertical heating, revealing how rotation influences convective heat transfer and flow structures.

Contribution

It provides new experimental insights into the effects of simultaneous radial and vertical temperature gradients on heat transport in rotating fluids.

Findings

Rotation reduces Nusselt number compared to non-rotating convection.

Flow structures include columnar plumes and baroclinic waves.

Rotation affects heat transfer efficiency and flow patterns.

Abstract

Laboratory experiments were conducted to study heat transport characteristics in a nonhomogeneously heated fluid annulus subjected to rotation along the vertical axis (z). The nonhomogeneous heating was obtained by imposing radial and vertical temperature gradient ({\Delta}T). The parameter range for this study was Rayleigh number, Ra=2.43x10^8-3.66x10^8, and Taylor number, Ta=6.45x10^8-27x10^8. The working fluid was water with a Prandtl number, Pr=7. Heat transport was measured for varying rotation rates ({\Omega}) for fixed values of {\Delta}T. The Nusselt number, Nu, plotted as a function of Ta distinctly showed the effect of rotation on heat transport. In general, Nu was found to have a larger value for non-rotating convection. This could mean an interplay of columnar plumes and baroclinic wave in our system as also evident from temperature measurements. Laser based imaging at a single vertical plane also showed evidence of such flow structure.