Optimization of nonlinear lateral characteristic of lifting-body type reentry vehicle

The nonlinear lateral characteristics of a lifting-body type reentry vehicle were improved by applying efficient optimization techniques to determine the optimum configuration. First, the causes for the nonlinear lateral characteristics were investigated by computational fluid dynamics analysis. The results indicated that fins mounted on the Japan Aerospace Exploration Agency's baseline lifting-body configuration cause unsymmetrical development of vortices and result in nonlinear lateral characteristics. An efficient optimization algorithm, called efficient global optimization for multiobjective problems, was adopted to improve these nonlinear lateral characteristics. Efficient global optimization for multiobjective problems predicts potential optimum solutions based on the probability estimated by the Kriging model. The computational time for optimization was markedly reduced owing to use of the Kriging model. Further investigations were also performed to determine the effects of the upswept upper-aft and swept-back fin angles. The results indicated that the swept-back fin angle is an important factor controlling the lateral characteristics of the lifting-body type reentry vehicle.