Coherent superstructures in turbulent pipe and Taylor-Couette flows

湍流管和 Taylor-Couette 流中的相干上部结构

• 批准号: 316065285
• 负责人: Professor Dr. Marc Avila Canellas
• 金额: --
• 依托单位: Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/316065285?language=en
• 关键词: Coherent; superstructures; turbulent; pipe; Taylor

Fluid motions in nature and engineering typically feature large-scale coherent motions, so-called superstructures, which are strongly shaped by boundary conditions, geometry and source of driving. Turbulent superstructures carry a substantial part of the kinetic energy, they contribute to drag and they often dominate heat, mass and momentum transport properties of the entire fluid system. Hence, in order to go beyond state-of-the-art modelling and control strategies of turbulent flows, superstructures must be correctly accounted for. In this project, we will investigate the dynamics, energetics and transport properties of superstructures in two canonical setups: cylindrical pipe flow and Taylor--Couette flow between two rotating concentric cylinders, especially in the narrow-gap limit. First, we will determine whether superstructures harvest energy through coherent alignment of much smaller scales, or directly from the mean shear. We will achieve this by computing the inter-scale energy flux from direct numerical simulation data with a (spatially) filtering approach. Second, in order to aid the groups developing characterisation and detection methods within the Priority Programme we will offer and maintain highly-resolved data sets, which will be adaptively reduced in spatial and temporal complexity using our filtering tools. With these methods, we will investigate the relationship between Lagrange coherent structures and energy fluxes. Our work will build upon the network of collaborations established in the first funding phase and will allow bridging the current gap towards high Reynolds numbers.

自然界和工程中的流体运动通常以大规模相干运动为特征，即所谓的上层建筑，它强烈地受到边界条件、几何形状和驱动力来源的影响。湍流超结构携带了相当大一部分动能，它们对阻力有贡献，它们往往主导着整个流体系统的热、质量和动量输运特性。因此，为了超越最先进的湍流建模和控制策略，必须正确地考虑上层建筑。在这个项目中，我们将研究两种正则系统中超结构的动力学、能量学和输运性质：圆柱管流动和两个旋转同心圆柱之间的Taylor-Couette流动，特别是在窄间隙极限下。首先，我们将确定超结构是通过小得多尺度的相干排列获得能量，还是直接从平均切变中获取能量。我们将通过(空间)滤波方法从直接数值模拟数据计算尺度间能量通量来实现这一点。第二，为了帮助各小组在优先方案范围内制定特征和检测方法，我们将提供和维护高分辨率的数据集，这些数据集将使用我们的过滤工具自适应地降低空间和时间的复杂性。利用这些方法，我们将研究拉格朗日相干结构与能量通量之间的关系。我们的工作将建立在第一个筹资阶段建立的合作网络之上，并将允许弥合目前向高雷诺数方向的差距。