Investigation of Turbulent Flow Separation and the Development of Flow Control Strategies for Bluff Bodies in Ground Proximity

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Flow separation and aerodynamics of bluff bodies (objects with boxy shapes like bricks or some road vehicles) are encountered in many industrial applications. The consequences of flow separation include significant pressure fluctuations that cause undesirable effects such as drag, structural vibration, noise and significant reductions in efficiency and performance of engineering systems. It is well-known that at highway speeds, for example, more than 50% of the fuel is used to overcome aerodynamic drag on road vehicles. For the above reasons, bluff body aerodynamics has been a subject of intensive research interests for many decades. However, for complex three-dimensional (3D) bluff bodies, some fundamental questions are not fully resolved: how do we accurately predict the drag on a 3D bluff body? The proposed research has three short-term objectives: i) characterize in detail the mean and fluctuating flow structures of a number of 3D bluff bodies in ground proximity; ii) develop advanced flow control strategies that are effective for 3D bluff bodies, and mechanistic parameters for quantifying them; and iii) develop accurate numerical models for fully capturing the complete aerodynamic phenomena on the bluff bodies. In order to meet the short-term objectives, a variety of 3D bluff bodies will be constructed. Velocity, pressure, and force measurements will then be conducted around the bluff bodies in wind and water tunnels using particle image velocimetry, hotwire, pressure sensors, and force sensors. In addition, numerical techniques will be employed for these studies using open source numerical codes. It is expected that over the next 5 years, 16 HQP (3 PhD, 3 MASc, and 10 undergraduate students) will be trained to perform detailed experiments and numerical simulations to enable them to gain a thorough physical understanding of bluff body aerodynamics. It is anticipated that a successful completion of the research program will provide new insight to illuminate our physical understanding of age-old fundamental questions. This can lead to the development of cost-effective flow control devices to improve the efficiency of engineering systems. It will also help reduce Canada's carbon footprint and its impacts on our climate. Additionally, HQP will develop useful skills for employment in academia or diverse industries of socio-economic importance to Canada.