Research on wing shapes optimization for gliding distance

Optimizing the aerodynamic layout is an important means to improve the flight efficiency of aircraft. For gliding unmanned aerial vehicles (UAVs) with foldable wings, represented by bionic flying fish, this work studies the optimization of wing surface shapes using surrogate models to improve the gliding distance of the UAVs. The wing surface shape is parameterized using Bezier polynomials, and the aerodynamic performance of a 3D bionic flying fish UAV is simulated using computational fluid dynamics (CFD) methods. A surrogate optimization model is established using Kriging method, and the Expected Improvement (EI) is selected to improve the fitting accuracy of the surrogate model. A three-degree-of-freedom gliding trajectory model of the aircraft is established, and the wing surface shape is optimized to maximize the gliding distance under specific operating conditions. The results show that the optimized wing surface shape has typical swept-back characteristics, and the leading edge of the wing surface deviates significantly from a straight line, exhibiting the morphological characteristics of a biological wing. The gliding distance obtained by optimizing the wing surface layout based on the lift-to-drag ratio is significantly smaller than that obtained by optimizing for the gliding distance. For different gliding conditions, the optimized wing surface shapes show significant differences. This indicates that there is a strong coupling between the wing surface shape and the flight conditions in determining the gliding distance. Therefore, in optimizing the wing surface shape, the flight conditions of the aircraft need to be considered appropriately to achieve the maximum gliding distance.