Prandtl-, Rayleigh-, and Rossby-number dependence of heat transport in turbulent rotating Rayleigh-Benard convection

TL;DR

This paper investigates how heat transfer in turbulent rotating Rayleigh-Benard convection depends on the Rayleigh, Prandtl, and Rossby numbers, revealing conditions where rotation enhances or does not affect heat transfer.

Contribution

It provides experimental and numerical analysis of heat transfer dependence on key dimensionless numbers in turbulent rotating convection, highlighting the role of Prandtl number and rotation.

Findings

Rotation can enhance heat transfer by up to 30% at certain parameters.

Heat transfer enhancement diminishes at higher Rayleigh numbers.

Small Prandtl number leads to no heat transfer enhancement due to thermal diffusion effects.

Abstract

Experimental and numerical data for the heat transfer as a function of the Rayleigh-, Prandtl-, and Rossby numbers in turbulent rotating Rayleigh-Benard convection are presented. For relatively small $Ra ~ 10^8$ and large Pr modest rotation can enhance the heat transfer by up to 30%. At larger Ra there is less heat-transfer enhancement, and at small Pr = 0.7. there is no heat-transfer enhancement at all. We suggest that the small-Pr behavior is due to the breakdown of the heat-transfer-enhancing Ekman pumping because of larger thermal diffusion.