Abstract : a large planar microphone array , which consists of 111 microphones , was successfully applied to obtain a two - dimensional mapping of the sound sources on a landing aircraft . the focus of study in this paper is on the landing gear noise source . the spectra , directivities and sound pressure levels of flap side - edge noise of 7 narrow - board commercial aircraft and 7 wide - board commercial aircraft are presented . it is found that the landing gear noise spectrum is broadband with some single tones in some cases . the directivity of the total sound pressure level of a landing gear noise resembles that of a horizontal dipole . the level differences between the various aircraft landing gears are larger than those expected from the airspeed differences . it is thus expected that the louder noise emission of the landing gears can be reduced by redesigning 文摘:应用由111个传声器组成的平面传声器阵列对当前流行的民用客机进场着陆过程中的机体噪声源进行了实验测量，本文对七架窄体客机和七架宽体客机的起落架噪声进行了分析，得到了起落架噪声的频谱特性、指向特性和声级变化.研究发现，起落架噪声的频谱是由宽频随机噪声与一些较为明显的单音噪声源组成，起落架噪声的指向性类似于一个水平放置的偶极子.不同飞机起落架噪声的声级相差较大，这说明可以通过重新结构设计降低起落架噪声。
