Turbulent flow through and over vegetation continues to draw significant research attention given its relevance to a plethora of applications in earth and environmental science. Canopy flows are characterized by three-dimensional coherent vortical motions not directly accessible from single-point measurements, which pose a challenge to formalizing links between vegetation structure and turbulent motion. A joint velocity-intermittency technique is applied to velocity data collected within and above aquatic vegetation in a hydraulic flume and above a forested canopy. The approach reveals behavior that provides greater insight into canopy flow dynamics than may be inferred from the vertical profiles of mean velocity, turbulence intensity and Reynolds stresses, which are the quantities usually studied. There is a remarkable similarity in the structure of such flows between the forest canopy and the flume study despite large differences in morphology and stem rigidity. In particular, these results determine an outer flow type arising above 1.5 canopy heights, while turbulent in-rushing events are most significant at the zero-plane displacement. The approach also implies ways in which improved models for canopy turbulence may be developed.

中文翻译：

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联合速度-间歇性分析揭示了大气层和水层冠层湍流在垂直结构上的相似性

由于与植物和地球科学中大量应用相关的湍流，在植被中流动的湍流一直吸引着大量的研究关注。冠层流的特征是无法从单点测量中直接获得三维相干涡旋运动，这对形式化植被结构与湍流之间的联系提出了挑战。联合速度间歇技术适用于在水力水渠中的水生植被内部和上方以及林冠层上方收集的速度数据。这种方法所揭示的行为，比从通常研究的平均速度，湍流强度和雷诺应力的垂直剖面可以推断出的树冠流动动力学更深入。尽管在形态和茎干硬度方面存在很大差异，但在林冠层和水槽研究之间，这种流动的结构具有显着相似性。特别是，这些结果确定了在1.5冠层高度以上产生的外流类型，而湍流的冲入事件在零平面位移处最为明显。该方法还暗示了可以开发用于冠层湍流的改进模型的方式。