Laminar superlayer at the turbulence boundary.
Laminar superlayer at the turbulence boundary.
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DOI：
10.1103/physrevlett.106.134503
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发表时间：
2011-03
影响因子：
8.6
通讯作者：
M. Holzner;B. Lüthi
中科院分区：
文献类型：
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作者：
M. Holzner;B. Lüthi
在这封信中，我们提出的结果，从粒子跟踪测速和直接数值模拟是一致的层流超层的存在，提出了在Corrsin和奇石勒的开创性工作（NACA，技术报告第1244号，1955年）。我们发现，当地的超层速度是由粘性分量占主导地位，其幅度是可比的最小尺度的运动的特征速度。这种缓慢的粘性过程涉及大的表面积，使得湍流传播的全局速率由最大的运动尺度设定。这些发现对于更好地理解存在薄剪切层的各种流动中的质量和动量的混合是重要的。例如边界层、云、行星大气和海洋。
In this Letter we present results from particle tracking velocimetry and direct numerical simulation that are congruent with the existence of a laminar superlayer, as proposed in the pioneering work of Corrsin and Kistler (NACA, Technical Report No. 1244, 1955). We find that the local superlayer velocity is dominated by a viscous component and its magnitude is comparable to the characteristic velocity of the smallest scales of motion. This slow viscous process involves a large surface area so that the global rate of turbulence spreading is set by the largest scales of motion. These findings are important for a better understanding of mixing of mass and momentum in a variety of flows where thin layers of shear exist. Examples are boundary layers, clouds, planetary atmospheres, and oceans.