Instantaneous measurement of velocity fields in developed thermal turbulence in mercury.
Instantaneous measurement of velocity fields in developed thermal turbulence in mercury.
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DOI：
10.1103/physreve.69.036306
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发表时间：
2003-10
期刊：
影响因子：
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通讯作者：
T. Mashiko;Y. Tsuji;Takatoshi Mizuno;M. Sano
中科院分区：
文献类型：
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作者：
T. Mashiko;Y. Tsuji;Takatoshi Mizuno;M. Sano
使用超声波测速仪，我们测量了高瑞利数的热对流在一个细胞的纵横比为0.5，充满了低普朗特数的流体，汞的速度波动的垂直剖面。利用谱分解和重建，阐明了平均流的有趣的脉动动力学和动能级联的普遍性质。结构函数和能谱的标度性质直接计算，而不使用泰勒的冻结流假设。尽管平均流动的复杂性，它被发现，能量级联过程中表现出普遍的规律，在热湍流。
Using ultrasonic velocimetry we measured the vertical profile of the velocity fluctuation in high-Rayleigh-number thermal convection in a cell with aspect ratio of 0.5, filled with a low-Prandtl-number fluid, mercury. The intriguing fluctuating dynamics of the mean flow and universal nature of the kinetic energy cascade are elucidated utilizing spectral decomposition and reconstruction. The scaling properties of the structure functions and the energy spectrum are directly calculated without the use of Taylor's frozen-flow hypothesis. Despite the complex nature of the mean flow, it is found that the energy cascade process exhibits universal laws in thermal turbulence.