Expanding the Osculating Flowfield Waverider Method Beyond Power Law Body Induced Flowfields

摘要

The Osculating Flowfield Method of waverider geometry generation has been in existence for over ten years. During that time, many successful applications of the method have been found. The original method employed a series of power law body induced flowfields on each osculating plane. While using this set of flowfields has proven to be quite powerful in defining a wide design space across while waverider vehicles could be optimized, there are limitations to what geometries a collection of such flowfields can produce. Recent work in waverider optimizations directed towards reducing transonic wave drag and sonic boom shaping has highlighted these limitations. The current work is focused on expanding the flowfields available to the Osculating Flowfield Method. A series of Bezier Curves have been employed to represent the vehicle geometry on the osculating flowfields. By manipulating the locations of the control points for the Bezier Curves, a wider variety of such geometries can be produced. For each geometry, the effective shock wave angle is required to scale the local waverider geometry. This shock angle was found for each unique Bezier Curve geometry using either a two-dimensional planar or a two-dimensional axisymmetric Method of Characteristics approach to quickly generate the inviscid shock wave shape. The effective shock wave angle was then determined from these shock shapes. The expanded Osculating Flowfield Method was used with a Particle Swarm Optimization scheme to define optimum waverider configurations for maximized inviscid lift-to-drag ratio, with and without a fixed lift coefficient for both Caret-type waveriders and for generalized three-dimensional waverider configurations. The development of the new approach, along with trend lines and Pareto fronts for the resulting waverider performance, are presented.