涡波一体乘波飞行器宽速域气动优化设计研究

The vortex-shock integrated wide-speed-range waverider could significantly improve aerodynamic performances of the traditional waverider at the low-speed state by introducing vortex effect, and has potential to be widely used in the overall aerodynamic design of the wide-speed-range aerospace vehicle in the future. However, the design of the vortex-shock integrated waverider does not consider the three-dimensional effect, low-speed effect, viscous effect and head/leading edge passivation effect during the establishment of reference flow field. So it still has potential to improve the wide-speed-range performances of the vortex-shock integrated waverider with the aerodynamic shape optimization method. In order to solve this problem, this paper develops an aerodynamic optimization design method for aircraft in wide speed range based on discrete adjoint by combining high-fidelity RANS solver, free deformation parameterization method, robust structural mesh deformation method, discrete adjoint method and sequential quadratic programming algorithm. Through the method, the aerodynamic optimization design in the wide speed range based on discrete adjoint is used to carry out for the vortex-shock integrated waverider in the subsonic and hypersonic flight conditions. The optimum configuration in the wide speed range is obtained through the aerodynamic optimization design and the flow mechanism is analyzed. The results show that compared with the original configuration, the optimum one increases the lift and lift-to-drag ratio of the vortex-shock integrated waverider more than 10% at low speed, while keeping the hypersonic lift and drag aerodynamic performance of the vehicle not fall. The performance improvement of the vehicle at low speed is attributed to the significant enhancement of the leeward vortex effect, resulting in a larger area of low pressure on the leeward surface to effectively increase the lift. The research shows that the gradient optimization based on discrete adjoint could further improve the aerodynamic performances of the vortex-shock integrated wide-speed-range waverider at high and low speed.