低勃朗特数雷利-贝纳德对流中的热边界层动力学

IF 3.6 2区 工程技术 Q1 MECHANICS
Nayoung Kim, Felix Schindler, Tobias Vogt, Sven Eckert
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引用次数: 0

摘要

在这项实验研究中,我们探索了液态金属雷利-贝纳德对流中热边界层的动力学,涵盖的参数范围为 0.026 \leq$ Prandtl 数 $ (Pr) \leq 0.033$ 和雷利数 ( $Ra$ ) 高达 2.9/times 10^9$ 。我们的研究重点是确定长宽比为 0.5 的圆柱形对流单元顶板附近热边界层的特征,区分两个不同的区域:顶板中心周围以剪切力为主的区域和靠近侧壁的位置,预计边界层会受到热羽流冲击或喷射的影响。在这些位置,边界层厚度对 $Ra$ 的依赖关系显示出不同的缩放指数,差异随着 $Ra$ 的增加而减小。我们发现随着 $Ra$ 的增加,边界层的波动更强,与普朗特-巴拉斯-波尔豪森曲线的偏差也越来越大,中心区域以外的测量结果也是如此。我们的数据说明了低 $Pr$ 对流中流动动力学与热传输之间复杂的相互作用。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Thermal boundary layer dynamics in low-Prandtl-number Rayleigh–Bénard convection
In this experimental study, we explore the dynamics of the thermal boundary layer in liquid metal Rayleigh–Bénard convection, covering the parameter ranges of $0.026 \leq$ Prandtl numbers $(Pr) \leq 0.033$ and Rayleigh numbers ( $Ra$ ) up to $2.9\times 10^9$ . Our research focuses on characterising the thermal boundary layer near the top plate of a cylindrical convection cell with an aspect ratio of 0.5, distinguishing between two distinct regions: the shear-dominated region around the centre of the top plate and a location near the side wall where the boundary layer is expected to be affected by the impact or ejection of thermal plumes. The dependencies of the boundary layer thickness on $Ra$ at these positions reveal deviating scaling exponents with the difference diminishing as $Ra$ increases. We find stronger fluctuations in the boundary layer and increasing deviation from the Prandtl–Blasius–Pohlhausen profile with increasing $Ra$ , as well as in the measurements outside the centre region. Our data illustrate the complex interplay between flow dynamics and thermal transport in low- $Pr$ convection.
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来源期刊
CiteScore
6.50
自引率
27.00%
发文量
945
审稿时长
5.1 months
期刊介绍: Journal of Fluid Mechanics is the leading international journal in the field and is essential reading for all those concerned with developments in fluid mechanics. It publishes authoritative articles covering theoretical, computational and experimental investigations of all aspects of the mechanics of fluids. Each issue contains papers on both the fundamental aspects of fluid mechanics, and their applications to other fields such as aeronautics, astrophysics, biology, chemical and mechanical engineering, hydraulics, meteorology, oceanography, geology, acoustics and combustion.
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