Aerodynamic Optimization of a Three-Dimensional High-Lift System Considering Mechanical Feasibility

Aerodynamic optimization methods considering the mechanism design of high-lift systems have been proposed to address the contradiction and tradeoff between aerodynamic and mechanical performance inherent in conventional decoupling methods. However, existing two-dimensional optimization methods lack the ability to ensure the feasibility of realistic three-dimensional mechanisms. In this paper, an aerodynamic optimization of a three-dimensional high-lift system considering mechanical feasibility is conducted to optimize the flap shape and setting. The NSGA-II algorithm is employed to identify the aerodynamically optimal and mechanically feasible configuration. The result shows that the lift coefficient of the optimized configuration increases by 1.4% for takeoff and 8.8% for landing at an 8° angle of attack, within the mechanical constraints. Further analysis indicates that the mechanical feasibility is significantly influenced by the combination of flap overlap and gap for takeoff and landing. And the feasible design space is extremely shrunk due to mechanical constraints. A comparison with a conventional two-dimensional optimization method reveals the superior capability and necessity of the proposed three-dimensional method in both enhancing aerodynamic performance and ensuring mechanical feasibility.