Nogueira Petrônio A S, Sirotto José R L N, Miotto Renato F, Cavalieri André V G, Cordioli Julio A, Wolf William R
Divisão de Engenharia Aeronáutica, Instituto Tecnológico de Aeronáutica, São José dos Campos, SP, 12228-900, Brazil.
Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, SC, 88040-900, Brazil.
J Acoust Soc Am. 2019 Jul;146(1):50. doi: 10.1121/1.5115006.
Acoustic measurements of turbulent jets in the vicinity of a flat plate, mimicking a neighbouring wing, were compared to results from two wavepacket-based source models previously studied in the literature: the Tailored Green's Function method, which considers the radiation of the turbulent structure in the vicinity of a semi-infinite flat plate, and the Boundary Element Method, which can represent the full geometry of the plate used in the experiments. Particular interest is given to analysing how the angle of attack of the plate (α) affects the sound radiated by an installed jet with trailing edge 6 diameters away from the nozzle and 1 diameter away from the centerline for 0° ≤ α ≤ 45°. The results herein confirm the behaviour identified by the models: the scattered acoustic field follows the rotation of the plate, shifting a silence region with negligible scattered sound, and creating regions with lower noise levels in positions that correspond to the ground for an aircraft with engines under its wings. This is further explored by means of a Mach number analysis for M = 0.5, 0.7, and 0.9, showing that this trend is present whenever trailing-edge scattering of jet disturbances is dominant in the acoustic field.
对模拟相邻机翼的平板附近湍流射流的声学测量结果，与文献中先前研究的两种基于波包的源模型的结果进行了比较：定制格林函数方法，该方法考虑半无限平板附近湍流结构的辐射；边界元方法，该方法可以表示实验中使用的平板的完整几何形状。特别关注分析平板的攻角（α）如何影响安装的射流所辐射的声音，该射流的后缘距离喷嘴6个直径且距离中心线1个直径，攻角范围为0°≤α≤45°。本文的结果证实了模型所确定的行为：散射声场跟随平板的旋转，移动了散射声可忽略不计的静音区域，并在对应于机翼下方有发动机的飞机地面位置处创建了噪声水平较低的区域。通过对马赫数M = 0.5、0.7和0.9进行分析进一步探讨了这一点，结果表明，只要射流扰动的后缘散射在声场中占主导地位，这种趋势就会出现。
