Shape and trajectory optimisation of hypersonic waveriders

Abstract

Waveriders are high-lifting hypersonic configurations with great potential to become a future reusable launch vehicle concept. However, in a re-entry flight scenario, standard waverider designs face challenges such as stability, controllability, heat load management, and performance at off-design conditions. In this research, a baseline waverider design is established and then modified to feature blunt leading edges, aerodynamic surfaces for trim and control, and fins for lateral-directional stability. Shape variations are then introduced using central-composite designs, and the re-entry trajectories of all generated vehicles are optimised numerically in a constrained multi-objective framework. Performance indices (cross-range, heat load, pitch stability, lateral-directional stability and aileron controllability) are computed for each optimal trajectory, and response surfaces relating them with the shape variables are constructed and optimised independently using an interior point method. From this process, desirable, irrelevant and conflicting shape features for the various performance indices are identified. A novel local surface inclination method blending the tangent-wedge and modified Newtonian models was introduced to compute the aerodynamic force and moment coefficients of the waveriders. Finally, an existing program to compute the convective heat flux on the surface of blunt-nosed vehicles at hypersonic speeds was computationally optimised, and then extended to support waverider-like geometries with leading edges and stagnation lines.