Confined inclined thermal convection in low-Prandtl-number fluids
Confined inclined thermal convection in low-Prandtl-number fluids
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DOI：
10.1017/jfm.2018.477
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发表时间：
2018-07
影响因子：
3.7
通讯作者：
Lukas Zwirner;O. Shishkina
中科院分区：
文献类型：
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作者：
Lukas Zwirner;O. Shishkina
瑞利-贝纳德对流单体的任何倾斜都会改变其内部的整体流动结构，从而导致热量和动量传输的变化。特别敏感的倾角是在低普朗特数流体和受限的几何形状的热传输。本文研究了直径与高度之比为$\unicode[STIX]{x1 D 6 E4}=1/5$的圆柱形容器内倾斜对流的整体流动结构及其对整体热输运的影响。该研究基于直接数值模拟，其中考虑了两个不同的普兰特数$Pr=0.1$和1.0，而Rayleigh数$Ra$的范围从$10^{6}$到$10^{9}$。对于$Ra$和$Pr$的每个组合，倾斜角在0和$\unicode[STIX]{x 03 C 0}/2$之间变化。确定了对流单体的最佳倾角，该倾角提供了最大的全局热传输。对于倾斜对流，我们观察到形成两个系统大小的羽柱，一个热的和一个冷的，撞击在相反的边界层。这些都与热传输的强烈增加有关。
Any tilt of a Rayleigh–Bénard convection cell against gravity changes the global flow structure inside the cell, which leads to a change of the heat and momentum transport. Especially sensitive to the inclination angle is the heat transport in low-Prandtl-number fluids and confined geometries. The purpose of the present work is to investigate the global flow structure and its influence on the global heat transport in inclined convection in a cylindrical container of diameter-to-height aspect ratio $\unicode[STIX]{x1D6E4}=1/5$ . The study is based on direct numerical simulations where two different Prandtl numbers $Pr=0.1$ and 1.0 are considered, while the Rayleigh number, $Ra$ , ranges from $10^{6}$ to $10^{9}$ . For each combination of $Ra$ and $Pr$ , the inclination angle is varied between 0 and $\unicode[STIX]{x03C0}/2$ . An optimal inclination angle of the convection cell, which provides the maximal global heat transport, is determined. For inclined convection we observe the formation of two system-sized plume columns, a hot and a cold one, that impinge on the opposite boundary layers. These are related to a strong increase in the heat transport.