2007 年 2 巻 3 号 p. 567-577
The present study is a technical report of the multi-objective design optimization of the two-dimensional shielding effect for the reduction of aircraft engine fan noise. The design optimization has been performed for the simplified cross section of aircraft with fuselage and plane wing. Two objective functions are considered for minimizing the sound pressure level at the side and the bottom locations relative to the fuselage, where standard measuring locations are defined by International Civil Aviation Organization. Those values are evaluated by using the linearized Euler equations. Since a wing, which is defined as a plate without thickness, is assumed as a V-tail wing, it is described by using the length and cant angle relative to the fuselage. The kriging-based response surface model is selected as an optimizer for the reduction of optimization cost. As a result, it is revealed that engine fan noise described by a monopole sound source is reduced by the shielding effect. Moreover, there is no tradeoff between two objective functions, i.e., the sound pressure levels at the side and the bottom measuring locations can be simultaneously reduced. As it is better that the wing length is as long as possible, the cant angle is essential for the shielding effect to reduce engine fan noise.
