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

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.