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

1236527/1235726最佳/星期四在多孔的、可渗透的表面上移动的湍流在许多环境和工业流动中是普遍存在的，例如在河流中、在植被覆盖的树冠上、在热交换器、膜管反应器和烃威尔斯井中。然而，尽管这些流动在许多科学分支中具有广泛的重要性，但对可渗透边界上的湍流物理学仍然知之甚少，目前阻碍了我们预测气体，颗粒，微生物和污染物进出此类表面的能力。该项目将开发和利用光流测量的最新技术，以提供关于可渗透表面上方和内部3D流动结构的独特新数据，以及这些流动之间的相互作用。该项目预计将改变地表-地下湍流相互作用的理解，并能够测试有关此类表面上湍流性质的几个关键问题，以及这种流动结构如何随着渗透床类型的改变和上覆流速的变化而变化。实验室实验将使水流和沉积物的折射率相匹配，从而能够在可渗透沉积层之上和之内进行光学测量。此外，新的全光相机技术将用于量化3D体积内的三维流动，包括可渗透表面内和可渗透表面上方。这些技术的结合开辟了定量信息的可能性，这是以前从未在如此复杂的流动中获得过的。该项目将使两名博士生在合作和跨学科的研究环境中的最先进的实验技术的培训。这些独特的数据将允许开发新的概念模型的流动在可渗透的表面，并提供必要的数据，以指导随后的数值模拟这些流量。这些数据将被用来解释如何湍流的可渗透表面的范围内移动可能会被修改的渗透性，从而检查流体动力学控制的命运的细颗粒移动穿过流体-沉积物界面。例如，这些结果将与解释自然河床的行为直接相关，其中砾石可能会被细粒沉积物填充，并且可以控制表面和地下流动之间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.