Collaborative Research: Modifications of turbulent boundary layer structure by wall permeability and surface-subsurface interactions: an innovative experimental approach

1236527/1235726最佳/Thurow浊流在许多环境和工业流体中普遍存在，例如在河流、植被覆盖的树冠、热交换器、膜管反应器和碳氢化合物井中。然而，尽管这些流动在许多科学分支中具有广泛的重要性，但穿越可渗透边界的湍流物理仍然知之甚少，目前阻碍了我们预测气体、颗粒、微生物和污染物进出这些表面的能力。该项目将开发和利用光学流动测量的最新技术，以提供关于可渗透表面上方和内部的3D流动结构的独特新数据，以及关键是这些流动之间的相互作用。该项目有望改变对地表-地下湍流相互作用的理解，并能够测试几个关键问题，这些问题涉及此类表面上的湍流性质，以及这种流动结构如何随着可渗透床的类型和上覆流速的变化而变化。实验室实验将匹配水流和沉积物的折射率，从而允许在可渗透沉积物床上方和内部进行光学测量。此外，新的全光摄像技术将被用来量化三维体积内的三维流动，包括在可渗透表面内和之上。这些技术的结合开启了在如此复杂的流动中以前从未获得过的定量信息的可能性。该项目将使两名博士生能够在协作和跨学科的研究环境中接受最先进的实验技术培训。这些独特的数据将允许开发新的可渗透表面流动的概念模型，并提供必要的数据来指导随后对这些流动进行数值模拟。这些数据将被用来解释在一系列可渗透表面上移动的湍流如何受到渗透率的影响，从而研究流体动力学对通过流体-沉积物界面移动的细颗粒的命运的控制。例如，这些结果将直接与解释天然河床的行为有关，在天然河床上，砾石可以被细粒沉积物填满，并可以控制表面和地下水流之间的纳米颗粒和污染物的交换。

1236527/1235726Best/ThurowTurbulent flows moving over a porous, permeable, surface are ubiquitous in many environmental and industrial flows, such as in rivers, over vegetated canopies, in heat exchangers, membrane tube reactors and hydrocarbon wells. However, despite the widespread importance of these flows in many branches of science, the physics of turbulence across permeable boundaries remains poorly understood, and currently hampers our ability to predict the movement of gases, particles, microbes and pollutants into and out of such surfaces. This project will develop and utilize the latest techniques in optical flow measurement to provide unique new data on the structure of 3D flow above and within permeable surfaces, and critically the interactions between these flows. The project is expected to transform the understanding of surface-subsurface turbulent flow interactions, and enable testing of several key questions concerning the nature of turbulence over such surfaces, and how this flow structure changes as the type of permeable bed is altered and the overlying flow velocity is varied. Laboratory experiments will match the refractive index of the flow and sediment, thus permitting optical measurements to be achieved above and within permeable sediment beds. Additionally, new plenoptic camera techniques will be used for the quantification of three-dimensional flow within a 3D volume, both within and above the permeable surface. The combination of these techniques opens up the possibility of quantitative information that has never been gained before within such complex flows. The project will enable the training of two PhD students in state-of-the-art experimental techniques within a collaborative and interdisciplinary research environment. These unique data will allow development of new conceptual models for flow over permeable surfaces and provide essential data to guide subsequent numerical modelling of these flows. These data will be used to explain how turbulent flows moving over a range of permeable surfaces may be modified by the permeability, and thus examine the fluid dynamic controls on the fate of fine particles moving across the fluid-sediment interface. For instance, these results will be of direct relevance in interpreting the behavior of natural river beds, where gravels can become infilled with fine-grained sediment, and which can control the exchange of nanoparticulates and contaminants between surface and subsurface flows.