Fundamental Understanding of Turbulent Flow over Fluid-Saturated Complex Porous Media

对于揭示自然现象(例如土壤蒸发、森林和城市树冠、鸟类羽毛和河床)以及包括储能、流动/噪声控制、电子冷却、填充床核反应堆和金属泡沫热交换器在内的人造技术背后的物理基础，了解多孔介质上的湍流特性是至关重要的。在这些自然和工程应用中，对由流体饱和的多孔介质和流经它的流动组成的复合多孔流体系统中湍流流动和传热的基本认识的逐步改变，对于这类系统的表征和诊断分析是至关重要的。复合系统的流动和热特性在很大程度上取决于外部流动、下游尾迹和多孔介质中流体流动之间的相互作用。尽管这个问题在自然界和工程上具有明显的相关性和广泛的影响，但对于复合多孔性流体系统中湍流的流动和热特性，以及将多孔区和经过它的外部流体之间的流动和热物性交换联系起来的模型，显然缺乏基本的了解。特别是，多孔介质上的速度和热边界层的特征，理解通过多孔介质的流动通道的机制，可能的流动泄漏及其与尾流的相互作用，以及它们与多孔介质的几何特征的关系，仍然是主要的科学挑战。在这个雄心勃勃的合作项目中，我们将曼彻斯特大学和南安普顿大学的计算和建模专业知识与布里斯托尔大学的实验专业知识相结合，以从根本上了解湍流边界层、流动泄漏和下游尾流对流体饱和多孔介质流动和热特性的影响。这将被用来建立基于证据的界面流动和热模型，代表通过界面在两个区域之间交换流动属性。这些模型将被用来开发基于体积平均法的设计工具，该方法是研究多孔介质中输运的一种流行的低成本工程方法，用于实际规模的应用，其中孔尺度分析在计算上是不可行的。

Understanding of turbulent flow characteristics over porous media is central for unravelling the physics underlying the natural phenomena (e.g., soil evaporation, forest and urban canopies, bird feathers and river beds) as well as man-made technologies including energy storage, flow/noise control, electronics cooling, packed bed nuclear reactors and metal foam heat exchangers. In these natural and engineering applications, a step change in the fundamental understanding of turbulent flow and heat transfer in composite porous-fluid systems, which consists of a fluid-saturated porous medium and a flow passing over it, is crucial for characterisation and diagnostic analysis of such systems. Flow and thermal characteristics of the composite systems depends heavily on the interaction between the external flow, downstream wake, and the fluid flow in the porous media. Despite the clear relevance and wide-ranging impact of this problem in nature and engineering, there is a clear lack of fundamental understanding of the flow and thermal characteristics of turbulent flow in composite porous-fluid systems, and the models that relate the exchange of the flow and thermal properties between the porous region and the external fluid passing over it. In particular, the characterisation of the velocity and thermal boundary layers over the porous media, understanding the mechanisms governing flow passage through porous media, possible flow leakage and its interaction with the wake flow, as well as their relationship with the geometric characteristics of porous media, have remained major scientific challenges. This highlights the clear need for a systematic fundamental study aimed at understanding the flow and thermal characteristics of turbulent flow over realistic porous media and the relationship between the properties of porous substrate, the flow within the porous media and the structure of turbulent flow over and past the porous region.In this ambitious collaborative project, we combine the computational and modelling expertise at the University of Manchester and Southampton with the experimental expertise at the University of Bristol, to gain fundamental understanding of the turbulent boundary layer, flow leakage and downstream wake on the flow and thermal characteristics of fluid-saturated porous media. This will be used to establish evidence-based interface flow and thermal models, representing the exchange of flow properties between two regions through the interface. These models will then be used to develop a design tool based on the volume-averaged approach, which is a popular low-cost engineering approach for studying transport in porous media, for real-scale applications where the pore-scale analysis in computationally prohibitive.