A recalcitrant problem in the physics of turbulence is the representation of the tendency of large-scale anisotropic eddies to redistribute their energy content with decreasing scales, a phenomenon referred to as return to isotropy. An unprecedented dataset of atmospheric turbulence measurements covering flat to mountainous terrain, stratification spanning convective to very stable conditions, surface roughness ranging over several orders of magnitude, and Reynolds numbers that far exceed the limits of direct numerical simulations and laboratory experiments was assembled for the first time and used to explore the scalewise return to isotropy. The multiple routes to energy equipartitioning among velocity components are shown to be universal once the initial anisotropy at large scales, linked to turbulence generation, is accounted for.

中文翻译：

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大气边界层湍流非均质性的普遍回归

湍流物理学中的顽强问题是代表大型各向异性涡以减小的尺度重新分布其能量的趋势，这种现象称为回归各向同性。首次收集了前所未有的大气湍流测量数据集，涵盖了从平坦到山区的地形，对流至非常稳定条件的分层，表面粗糙度超过几个数量级以及雷诺数远远超过直接数值模拟和实验室实验的限制时间并用于探索按比例返回等向性。一旦考虑了与湍流产生有关的大尺度初始各向异性，速度分量之间的能量均分的多种途径就被证明是普遍的。