Browsing by Author "Jiang, Hao"

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    Aerodynamic shape optimization of co-flow jet airfoil using a multi-island genetic algorithm
    (AIP Publishing, 2022-12-07) Jiang, Hao; Xu, Min; Yao, Weigang
    The co-flow jet is a Zero-Net-Mass-Flux (ZNMF) active flow control strategy and presents great potential to improve the aerodynamic efficiency of future fuel-efficient aircraft. The present work is to integrate the co-flow jet technology into aerodynamic shape optimization to further realize the potential of co-flow-jet technology and improve co-flow jet airfoil performance. The optimization results show that the maximum energy efficiency ratio of lift-augmentation and drag-reduction increased by 203.53% (α=0◦) and 10.25% (α=10◦) at the Power-1 condition (power coefficient of 0.3), respectively. A larger curvature is observed near the leading edge of the optimized aerodynamic shape, which leads to the early onset of flow separation and improves energy transfer efficiency from the jet to the free stream. In addition, the higher mid-span of the optimized airfoil is characterized by accelerating the flow in the middle of the airfoil, increasing the strength of the negative pressure zone, thus improving the stall margin and enhancing the co-flow jet circulation.
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    Experimental design for a novel co-flow jet airfoil
    (Springer, 2023-12-01) Jiang, Hao; Yao, Weigang; Xu, Min
    The Co-flow Jet (CFJ) technology holds significant promise for enhancing aero-dynamic efficiency and furthering decarbonization in the evolving landscape of air transportation. The aim of this study is to empirically validate an optimized CFJ airfoil through low-speed wind tunnel experiments. The CFJ airfoil is structured in a tri-sectional design, consisting of one experimental segment and two stationary segments. A support rod penetrates the airfoil, fulfilling dual roles: it not only maintains the structural integrity of the overall model but also enables the direct measurement of aerodynamic forces on the test section of the CFJ air-foil within a two-dimensional wind tunnel. In parallel, the stationary segments are designed to effectively minimize the interference from the lateral tunnel walls. The experimental results are compared with numerical simulations, specifically focusing on aerodynamic parameters and flow field distribution. The findings reveal that the experimental framework employed is highly effective in characterizing the aerodynamic behavior of the CFJ airfoil, showing strong agreement with the simulation data.
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    Wing Design Optimization and Stall Analysis with Co-flow Jet Active Control
    (AIP Publishing, 2024-04-25) Jiang, Hao; Yao, Weigang; Zheng, Boda; Xu, Min
    Coupled with Co-flow Jet (CFJ) technology, the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was utilized for the multi-objective combination optimization of an Optimized Co-flow Jet (OCFJ) wing, based on National Advisory Committee for Aeronautics (NACA) 6421. A high-precision numerical simulation using the Delayed Detached Eddy Simulation (DDES) model was performed on the optimized wing to investigate the three-dimensional flow separation characteristics after static stall. The stall improvement was investigated by adjusting the momentum coefficient of the injection. The results show that the optimized wing exhibits significant improvements in aerodynamic performance and corrected aerodynamic efficiency. At an angle of attack of 10◦, the average lift increased by 16.25% and the drag decreased by 27.23% compared to the CFJ6421 wing, while effectively addressing the problem of low modified aerodynamic efficiency of the CFJ wing at lower angles of attack. By utilizing higher momentum and improving the boundary layer control capability, flow separation is effectively suppressed, thus achieving the goal of stall recovery of the CFJ wing.