Kriging法を用いた3要素翼配置の多目的最適化

In this paper, a multi-objective design optimization for a three-element airfoil consisted of a slat, a main wing, and a flap was carried out. The objective functions were defined as the maximization of lift coefficient at landing (C(sub l8)) and stall conditions (C(sub l20)) simultaneously. Genetic Algorithm (GA) was used as an optimizer. Although it has advantage of global exploration, its computational cost is expensive. To reduce the computational cost, the kriging model which was constructed based on several sample designs was introduced. The solution space was explored based on the maximization of Expected Improvement (EI) value corresponding to objective functions on the kriging model to consider the predicted value by knging model and its uncertainty at the same time. These solutions were used as additional samples to improve the model. In this study, 60 sample points are evaluated using the Reynolds averaged Navier-Stokes simulation (RANS) for the construction of the kriging model. Through the present exploration process, several designs were obtained with better performance than the baseline setting in each objective function. Main-effects of the design variables are calculated to recognize which design variable has an effect on the objective functions. This result suggests that the gap and the deflection of a flap have a remarkable effect on each objective function and the gap of a slat has an effect on C(sub l20). C(sub l20) is also affected by the gap and the deflection of a flap.
JAXA Special Publication
宇宙航空研究開発機構特別資料