OPTIMIZATION OF CONSTANT SHOCK ANGLE VARIABLE-MACH-NUMBER WAVERIDERS

To enhance the wide-speed-range performance of aircraft in the hypersonic regime and to investigate the influence mechanism of spanwise Mach number distribution on the flow characteristics of variable-Mach-number waveriders, this study constructs a spanwise Mach number distribution function incorporating multiple variation patterns. Based on the osculating cone theory under a constant shock angle constraint, a class of waverider configurations with continuous Mach number variation features is designed, followed by sensitivity analysis and multi-objective optimization. The sensitivity analysis results reveal that the half-cone angle and the upper Mach number limit play a dominant role in wide-speed-range shock matching. The optimization results, with the inviscid lift-to-drag ratio and volumetric efficiency as the objective functions, demonstrate that the optimal configurations on the Pareto front exhibit a characteristic "increase-decrease-increase" spanwise Mach number distribution pattern. This indicates that adjusting the positions of the distribution's extreme points can effectively coordinate aerodynamic and volumetric characteristics. Further analysis identifies a significant coupling and trade-off relationship among the inviscid lift-to-drag ratio, volumetric efficiency, and the lift-to-drag ratio fluctuation rate. To validate the design effectiveness, a comparison was made between the optimized configuration and a fixed-Mach-number configuration under strict constraints of identical planform shape and volume/volumetric efficiency. The results show that as the freestream Mach number increases from 10 to 30, the optimized configuration maintains a consistent advantage in terms of the inviscid lift-to-drag ratio. Furthermore, stability analysis indicates that the aerodynamic center of the optimized configuration nearly coincides with the center of mass, presenting a neutrally stable state. This characteristic theoretically offers the potential for the vehicle to achieve trim-free flight and superior maneuverability.