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arXiv · 2307.12525

Critical Prandtl number for Heat Transfer Enhancement in Rotating Convection

Mohammad Anas·Pranav Joshi
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Abstract

Rotation, which stabilizes flow, can enhance the heat transfer in Rayleigh-Bénard convection (RBC) through Ekman pumping. In this Letter, we present the results of our direct numerical simulations of rotating RBC, providing a comprehensive analysis of this heat transfer enhancement relative to non-rotating RBC in the parameter space of Rayleigh number ($Ra$), Prandtl number ($Pr$), and Taylor number ($Ta$). We show that for a given $Ra$, there exists a critical Prandtl number ($Pr_{cr}$) below which no significant heat transfer enhancement occurs at any rotation rate, and an optimal Prandtl number ($Pr_{opt}$) at which maximum heat transfer enhancement occurs at an optimal rotation rate ($Ta_{opt}$). Notably, $Pr_{cr}$, $Pr_{opt}$, $Ta_{opt}$, and the maximum heat transfer enhancement all increase with increasing $Ra$. We also demonstrate a significant heat transfer enhancement up to $Ra=2\times 10^{10}$ and predict that the enhancement would become even more pronounced at higher $Ra$, provided $Pr$ is also increased commensurately.

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BibTeXRIS

Mohammad Anas, Pranav Joshi. 2023-12-20. Critical Prandtl number for Heat Transfer Enhancement in Rotating Convection. https://doi.org/10.1103/physrevlett.132.034001

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