Optimization and Trajectory Analysis of Morphing Waveriders

Abstract

A waverider is a flight vehicle that creates a shock wave attached to the leading edge, which leads to high lift-to-drag ratio at a design Mach number. A morphing waverider changes the lower surface in order to keep the shock wave attached to the leading edge at a range of Mach numbers. The classic waverider design method creates the vehicle shape with sharp leading edges from a known flow field. This is unrealistic for vehicle design, first because real-world leading edges are rounded, and second because this method limits the design space of possible geometries to a small subset that generate flow fields that can be calculated analytically. This objective of this fundamental research was to bypass the current limitations facing round-leading-edge waverider optimization by including a reduced-order blunt-leading-edge model and a Computational Fluid Dynamics (CFD) algorithm in the optimization process. A new morphing methodology was created that could apply additional off-design features to the leading edge and lower surface of planar shock-derived waveriders. An analytical model for off-design waveriders was developed and used to optimize morphing waverider geometries alongside the CHAMPS+ CFD tool. The impact of morphing on waverider range was evaluated using a direct collocation trajectory optimization algorithm. While the analytical model and CFD tool predicted similar performance trends, the CFD based method was better suited to capture the complex features experienced by round-leading edge morphing waveriders. For both methods, the optimized morphing waverider geometries were predicted to give lift-to-drag ratio and range increases over non-morphing waveriders. To provide additional insights into the effects of morphing on round-leading-edge waverider performance, further morphing optimization iterations, as well as the addition of constraints which take into account real-world low-cost access to space considerations, are recommended.