This article extends the previous investigation of the spatial evolution of energy-containing motions in wall-bounded turbulent flows (Kannadasan et al., J. Fluid Mech., vol. 955, 2023, R1) by examining their scale-interactions through spectral analysis based on the spanwise scale decomposition of turbulent kinetic energy and the Reynolds stress transport equation. The energy-containing motions located at the inflow of a turbulent channel flow are artificially removed and the interscale transport mechanisms involved in their spatial evolution are studied. This scale interaction analysis reveals the presence of a significant inverse transfer of streamwise Reynolds stress from the near-wall streaks to larger scales in the spatial evolution of energy-containing motions. This transfer is due to the spanwise variation of streamwise velocity fluctuations, represented by $\partial u'/\partial z$ , which is the primary mechanism of streak instability. The analysis presented in this study also shows that the inverse cascade of spanwise energy may correspond to the regeneration of streamwise vortices in the process of reactivating the self-sustaining mechanism in the spatial evolution of energy-containing motions.

中文翻译：

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壁界湍流中含能运动空间演化过程中尺度的相互作用

本文扩展了先前对壁界湍流中含能运动的空间演化的研究（Kannadasan等人。,J.流体机械。，卷。 955, 2023, R1) 通过基于湍流动能的展向尺度分解和雷诺应力传递方程的谱分析来检查它们的尺度相互作用。位于湍流通道流入口处的含能运动被人为去除，并研究了其空间演化所涉及的跨尺度输运机制。这种尺度相互作用分析揭示了在含能运动的空间演化中，流向雷诺应力从近壁条纹到更大尺度的显着逆转移的存在。这种转移是由于流向速度波动的翼展变化造成的，由下式表示 $\部分u'/\部分z$ ，这是条纹不稳定的主要机制。本研究的分析还表明，展向能量的逆级联可能对应于含能运动空间演化中重新激活自维持机制过程中流向涡流的再生。