密冠层湍流中的能量传递与尺度组织
Energy transfer and scale organisation in dense canopy turbulence
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中文总结 AI 辅助
该研究揭示了密集淹没冠层流动中湍流的能量传递与尺度组织机制，明确了能量产生、传递的尺度特征及冠层柔性的影响，为冠层湍流提供了统一能量学解释。
中文摘要 AI 辅助
本研究识别了维持密集淹没冠层流动中湍流的尺度相关过程。采用尺度解析能量收支，确定了产生、压力-应变重分布及跨尺度传递主要发生的空间位置和尺度范围，以及这些过程如何将冠层与上方剪切流关联起来。研究表明，能量产生集中在界面剪切层，且限于狭窄的流向和展向尺度范围内；而冠层内的波动主要通过跨尺度传递和压力-应变重分布维持。冠层内动态活跃的尺度在很大程度上由外层结构决定，其组织和相干性受这些继承运动的调节。冠层界面的能量交换是非对称的，但并非单向：尽管主导传递方向是从外层流向冠层，但所有尺度都存在间歇性反向相互作用。最强烈的跨界面交换与更精细尺度的运动相关，而非大尺度结构，这表明极端界面能量通量主要由小尺度动力学控制。冠层的柔性会削弱外层结构的相干性，降低层间能量传递效率，从而改变冠层内波动的组织形式和尺度。这些结果阐明了密集冠层中湍流的组织与维持机制，提供了将相干结构与尺度依赖机制关联起来的统一能量学解释。
英文摘要
This study identifies the scale-dependent processes that sustain turbulence in dense submerged canopy flows. Using a scale-resolved energy budget, we determine where in space and at which scales production, pressure-strain redistribution, and inter-scale transfer predominantly occur, and how they link the canopy layer to the overlying shear flow. We show that energy production is localised at the interfacial shear layer, over a narrow range of streamwise and spanwise scales, while fluctuations within the canopy are primarily maintained through inter-scale transfer and pressure-strain redistribution. The dynamically active scales in the canopy are largely imposed by outer-layer structures, with their organisation and coherence mediated by these inherited motions. Energy exchange across the canopy interface is asymmetric but not unidirectional: although the dominant transfer is from the outer layer towards the canopy, intermittent reverse interactions occur at all scales. The most intense cross-interface exchanges are associated with finer-scale motions rather than large-scale structures, indicating that extreme interfacial energy fluxes are governed predominantly by small-scale dynamics. The flexibility of the canopy weakens the coherence of outer-layer structures and reduces the efficiency of inter-layer energy transfer, thereby altering both the organisation and scale of the fluctuations within the canopy. These results clarify how turbulence in dense canopies is organised and sustained, providing a unified energetic interpretation that links coherent structures to scale-dependent mechanisms.
