Constrained optimization of three-dimensional hypersonic vehicle configurations

Abstract

A new method has been developed for preliminary design optimization of arbitrary (nonaxisymmetric) hypersonic configurations in terms of aerodynamic wave drag. This optimization was accomplished while fixing certain parts of the geometry and maintaining the initial volume and length of the vehicle. Because of the large number of flow analysis evaluations required by this optimization algorithm, a fast and accurate analysis code based on modified Newtonian flow theory was used. This shape optimization method utilized an independent point-motion algorithm for each surface point. The spatial locations of the points defining each cross section were varied and a numerical optimization algorithm based on a quasi-Newton gradient search concept was used to determine the new optimal configuration. Two different configurations were optimized: a cone and a hypersonic plane configuration. Each of these configurations had certain individual cross sections or surface points fixed during the optimization process. Numerical results indicate a significant decrease in aerodynamic wave drag for simple and complex configurations at a low computing cost. The procedure is capable of accepting more complex flow field analysis codes.