Self-organized large-scale flow structures occur in a wide range of turbulent flows. Yet, their emergence, dynamics, and interplay with small-scale turbulence are not well understood. Here, we investigate such self-organized turbulent superstructures in three-dimensional turbulent Kolmogorov flow with large-scale drag. Through extensive simulations, we uncover their low-dimensional dynamics featuring transitions between several stable and metastable large-scale structures as a function of the damping parameter. The main dissipation mechanism for the turbulent superstructures is the generation of small-scale turbulence, whose local structure depends strongly on the large-scale flow. Our results elucidate the generic emergence and low-dimensional dynamics of large-scale flow structures in fully developed turbulence and reveal a strong coupling of large- and small-scale flow features.

中文翻译：

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广义Kolmogorov流中湍流上部结构的转变

自组织的大规模流动结构出现在广泛的湍流中。但是，它们的出现，动力学以及与小规模湍流的相互作用尚不十分清楚。在这里，我们研究在具有大阻力的三维湍流Kolmogorov流中的这种自组织湍流上部结构。通过广泛的模拟，我们发现了它们的低维动力学特性，这些动力学特性是阻尼参数在多个稳定和亚稳态大型结构之间的过渡。湍流上部结构的主要耗散机制是小尺度湍流的产生，其局部结构在很大程度上取决于大尺度的流动。