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.

自然界和工程学的流体运动通常具有大规模相干运动，所谓的上层建筑，它们是由边界条件，几何形状和驾驶源强烈影响的。湍流的上层建筑具有大部分动能，它们有助于阻力，并且通常主导着整个流体系统的热量，质量和动量传输特性。因此，为了超越最先进的建模和动荡流的控制策略，必须正确考虑上层建筑。在这个项目中，我们将研究两个规范设置中上层建筑的动力学，能量和运输特性：圆柱管流量和泰勒 - 泰勒 - couette-couette流在两个旋转的同心圆柱之间，尤其是在窄间隙极限下。首先，我们将确定上层建筑是通过相干比对收集能量，还是直接从平均剪切物中收获。我们将通过使用（空间）过滤方法从直接数值模拟数据中计算尺度间的能量通量来实现这一目标。其次，为了帮助这些小组在优先级程序中开发表征和检测方法，我们将提供并维护高度分辨的数据集，这些数据集将在空间和时间复杂性中使用我们的过滤工具自适应地降低。通过这些方法，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资金阶段建立的合作网络的基础上，并将允许将当前的差距弥合到雷诺数高的数字。