Piantanida Selene, Jaunet Vincent, Huber Jérôme, Wolf William R, Jordan Peter, Cavalieri André V G
Institute Pprime, 43 rue de l'Aérodrome, 86036 Poitiers, France.
Acoustic Department, Airbus Operations, 316 route de Bayonne, 31060 Toulouse, France.
J Acoust Soc Am. 2016 Dec;140(6):4350. doi: 10.1121/1.4971425.
Installed jet noise is studied by means of a simplified configuration comprising a flat plate in the vicinity of a round jet. The effects of Mach number, jet-plate radial distance, and trailing-edge sweep angle are explored. Acoustic measurements are performed using a traversable 18-microphone azimuthal array, providing pressure data at 360 points on a cylindrical surface surrounding the jet-plate system. Key observations include a decrease, with increasing Mach number, of the relative level of the scattered field in comparison to the uninstalled jet; an exponential dependence of the scattered sound pressure level on the radial jet-plate separation; and considerable sideline noise reductions with increasing sweep angle, with which there is an overall reduction in acoustic efficiency. The measurements are compared with results obtained using a kinematic wavepacket source model, whose radiation is computed in two ways. A TGF for a semi-infinite flat plate is used to provide a low-order approximation of the scattering effect. Use of a more computationally intensive boundary element method provides additional precision. Good agreement between model predictions and experiment, encouraging from the perspective of low-cost prediction strategies, demonstrates that the models comprise the essential sound generation mechanisms.
通过一个简化配置来研究安装后的射流噪声，该配置包括一个位于圆形射流附近的平板。探讨了马赫数、射流与平板的径向距离以及后缘掠角的影响。使用可移动的18麦克风方位阵列进行声学测量，在围绕射流 - 平板系统的圆柱面上的360个点提供压力数据。主要观察结果包括：与未安装射流相比，随着马赫数增加，散射场的相对水平降低；散射声压级与射流 - 平板径向间距呈指数关系；随着掠角增加，侧向噪声显著降低，同时声学效率总体降低。将测量结果与使用运动波包源模型获得的结果进行比较，该模型的辐射通过两种方式计算。使用半无限平板的TGF来提供散射效应的低阶近似。使用计算量更大的边界元方法可提供更高的精度。模型预测与实验之间的良好一致性，从低成本预测策略的角度来看令人鼓舞，表明这些模型包含了基本的声音产生机制。
