Research Department Acoustics Group, TCR AVA 1 63, 1 Avenue du Golf, 78288 Guyancourt, France.
J Acoust Soc Am. 2010 Oct;128(4):1647-55. doi: 10.1121/1.3478780.
Direct measurements of the wavenumber-frequency spectrum of wall pressure fluctuations beneath a turbulent plane channel flow have been performed in an anechoic wind tunnel. A rotative array has been designed that allows the measurement of a complete map, 63×63 measuring points, of cross-power spectral densities over a large area. An original post-processing has been developed to separate the acoustic and the aerodynamic exciting loadings by transforming space-frequency data into wavenumber-frequency spectra. The acoustic part has also been estimated from a simple Corcos-like model including the contribution of a diffuse sound field. The measured acoustic contribution to the surface pressure fluctuations is 5% of the measured aerodynamic surface pressure fluctuations for a velocity and boundary layer thickness relevant for automotive interior noise applications. This shows that for aerodynamically induced car interior noise, both contributions to the surface pressure fluctuations on car windows have to be taken into account.
在消声风洞中对紊流平板通道下方壁面压力脉动的波数-频率谱进行了直接测量。设计了一个旋转阵列，允许测量大面积上的完整的互功率谱密度图，即 63×63 个测量点。通过将空间-频率数据变换为波数-频率谱，开发了一种原始的后处理方法来分离声和空气动力激励载荷。还从包括漫射声场贡献的简单科科洛（Corcos）模型估算了声部分。对于与汽车内部噪声应用相关的速度和边界层厚度，测量到的声对表面压力脉动的贡献为测量到的空气动力表面压力脉动的 5%。这表明，对于空气动力引起的汽车内部噪声，必须考虑到车窗表面压力脉动的这两个贡献。
