Chameleon attractors in turbulent flows
Chameleon attractors in turbulent flows
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DOI：
10.1016/j.chaos.2023.113195
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发表时间：
2023-01-31
影响因子：
7.8
通讯作者：
Lucarini, Valerio
中科院分区：
文献类型：
--
作者：
Alberti, Tommaso;Daviaud, Francois;Lucarini, Valerio
湍流流动呈现出丰富的动力学，其起源于跨尺度的非平凡能量通量、非定常强迫和几何约束。这种复杂性表现在非双曲混沌、随机性、状态依赖持续性和不可预测性。所有这些特征都阻碍了对底层湍流（随机）吸引子的充分表征，而这将是解开这种复杂性的关键对象。在这里，我们使用最近提出的形式主义，以跟踪在一个充分发展的湍流具有大量的自由度的相空间轨迹跨尺度的结构特征的演变。我们的结果表明，湍流吸引子的普遍性的概念失败，因为它们的属性取决于我们关注的尺度。更具体地说，我们观察到的几何和拓扑性质取决于大尺度强迫，与故障的统计普遍性出现在惯性范围的开始，非线性相互作用控制的能量级联机制的发展。鉴于这种吸引子在时间和尺度上的变化性质，我们称它们为变色龙吸引子。
Turbulent flows present rich dynamics originating from non-trivial energy fluxes across scales, non-stationary forcings and geometrical constraints. This complexity manifests in non-hyperbolic chaos, randomness, state -dependent persistence and unpredictability. All these features have prevented a full characterization of the underlying turbulent (stochastic) attractor, which will be the key object to unpin this complexity. Here we use a recently proposed formalism to trace the evolution of the structural characteristics of phase -space trajectories across scales in a fully developed turbulent flow featuring a huge number of degrees of freedom. Our results demonstrate the failure of the concept of universality of turbulent attractors since their properties depend on the scale we are focusing on. More specifically, we observe that the geometrical and topological properties depend on the large-scale forcing, with a breakdown of statistical universality emerging at the beginning of the inertial range, where nonlinear interactions controlling the energy cascade mechanism develop. Given the changing nature of such attractors in time and scales we term them chameleon attractors.