Aerodynamics and aeroacoustics of turbulent flows over and past permeable rough surfaces

各种湍流要么在多孔表面上，要么在具有表面多孔性的物体的尾流中。进化、工程设计、制造限制和自然现象导致这些多孔表面的粗糙和可渗透边界（例如热交换器、森林和城市树冠、鸟类羽毛和河床中的流动）。多孔表面的渗透性和粗糙度改变了在其上发展的湍流边界层，从而改变了经过具有表面多孔性的物体的尾流。这完全取决于粗糙面或尾迹上方边界层中的外部流动与多孔介质内流场之间的相互作用。尽管广泛的影响和相关性，有一个明显的缺乏基本的理解和比例关系的多孔介质的特性的外部流的功能的法律。这表明了明确需要一个系统的基础研究，旨在了解流动机制和多孔基质的性质之间的关系，多孔介质内的流场和湍流的结构，并通过他们。在这个雄心勃勃的合作项目中，我们联合收割机结合在南安普顿和布里斯托的实验专业知识与计算和建模专业知识在剑桥和南安普顿，以获得基本的了解湍流边界层和尾流超过和过去的可渗透粗糙表面。这将被用来开发一个充分验证的建模框架，可以预测与现实的多孔表面相互作用的湍流的空气动力学和航空声学。具体而言，我们将（1）使用高保真实验检查多孔表面上发展的壁湍流的空气动力学和航空声学特性，（2）我们将使用新的内部工具对多孔表面上的流动进行详细的DNS和LES，以了解多孔介质内的内部流动和外部流动之间的相互作用，（3）利用实验数据和数值模拟数据建立新的模型来描述多孔表面内外流之间的相互作用，（4）利用LES中的新模型预测空气动力学和声学;（5）在大范围的雷诺数范围内，对流过和经过可渗透粗糙表面的气流的空气动力学和气动声学进行测量，以进一步了解以及验证我们的新模型。最终，这将使我们和我们的行业合作伙伴能够研究不同的真实多孔表面在流动/噪声控制中的效用。

A variety of turbulent flows are either over porous surfaces or in the wake of bodies with surface porosity. Evolution, engineering design, manufacturing constraints and natural phenomena lead to rough and permeable boundaries in these porous surfaces (e.g. flow in heat exchangers, forest and urban canopies, bird feathers and river beds). The permeability and the roughness of a porous surface alters the turbulent boundary layer that develops over it and consequently the wake past an object with surface porosity. This entirely depends on the interaction between the external flow in the boundary layer over the roughness or the wake and the flow field within the porous media. Despite the wide-ranging impact and relevance, there is a clear lack of fundamental understanding and the scaling laws that relate the properties of porous media to the features of external flow. This points to the clear need for a systematic fundamental study aimed at understanding the flow mechanisms and the relationship between the properties of porous substrates, the flow field within the porous media and the structure of turbulent flow over and past them.In this ambitious collaborative project we combine the experimental expertise at Southampton and Bristol with the computational and modelling expertise at Cambridge and Southampton, to gain fundamental understanding of the turbulent boundary-layer and wake flow over and past permeable rough surfaces. This will be used to develop a fully-validated modelling framework that can predict the aerodynamics and aeroacoustics of turbulent flows interacting with realistic porous surfaces. Specifically, we will (1) examine the aerodynamic and aeroacoustic characteristics of wall-turbulence that develop over porous surfaces using high-fidelity experiments, (2) we will perform detailed DNS and LES of flow over porous surfaces using new in-house tools to understand the interaction between internal flow within the porous media and external flows, (3) use the experimental and numerical data to develop new models to represent the interaction between internal and external flow of porous surfaces in other lower fidelity simulations, (4) Utilise the new models in LES to predict the aerodynamics and aeroacoustics and (5) carry out measurements on the aerodynamics and aeroacoustics of flow over and past permeable rough surfaces over a large range of Reynolds numbers to further our understanding as well as to validate our new models. Ultimately, this will enable us and our industry partner to examine the utility of different realistic porous surfaces in flow/noise control.