Grant: Discovery Grants Program - Individual

Flow separation under extreme freestream turbulence (FST) conditions is a common phenomenon in nature and diverse engineering applications. Examples include flows around buildings and wind turbines in atmospheric turbulent boundary layer (ATBL), vehicles in open-road or wind gust conditions, and flow beneath river ice covers. Flow separation induces unsteady aerodynamic loads, negatively impacts the integrity of engineering structures such as wind turbines, and reduces fuel efficiency of road vehicles. Also, flow separation beneath an ice cover can significantly alter river ice transport processes, change the local hydraulic conditions and decrease the conveyance and operational efficiency of hydroelectric power systems, resulting in loss of power generation revenue. Understanding the effects of FST on separated flows is essential for the design of innovative control strategies to mitigate their negative impacts, reduce aerodynamic drag on vehicles or improve efficiency of power generating systems. A novel experimental research program is proposed to evaluate the effects of FST on flow separation around prisms mounted on a wall, partially submerged beneath a free surface, or placed in a uniform flow. The main goal of the research is to provide scientific understanding of the unsteady dynamics of these flows, and create a repository of databases that will enable the research community to develop reliable predictive tools and innovative control strategies for separated flows. The short-term objectives, which will be achieved over the next 5 years, are to evaluate the impacts of FST on the turbulence characteristics and unsteady flow dynamics. Over this 5-year cycle, 23 HQP (7 PhD, 6 MSc and 10 BSc) will be trained to perform novel experiments, apply turbulence theories to analyze their data and obtain unrivalled understanding of flow separation under FST conditions. These skills will prepare HQP for employment in academia, aerospace or power generation industries. This work will take place in a world-class research facility at the U Manitoba. Major lab features include an open water tunnel and a high-speed particle image velocimetry (PIV) system, which makes it possible to perform instantaneous and simultaneous measurements of all three velocity components on a magnitude that has never been achieved in the experimental study of flow separation under different FST conditions. Turbulence generating grids will be used to produce FST levels that mimic those found in ATBL, wind gust and realistic river ice conditions. The experimental results will facilitate the development of reliable numerical models which will enable the engineering community to reduce its reliance on physical model testing. The improved understanding acquired from this research will lead to the development of innovative technologies and design of energy efficient and environmentally-friendly engineering systems in the power generation industries and wind engineering community.