The Journal of the Acoustical Society of America · 2010 · 119 citations · 22 references
AeroacousticsEngineeringNoise PredictionAtmospheric AcousticAnechoic Wind TunnelOcean AcousticsNoiseFrequency SpectrumAcoustical EngineeringSound PropagationAcoustic AnalysisHealth SciencesAcoustic MethodsAerodynamic NoiseExternal AerodynamicsNoise MeasurementWall Pressure FluctuationsAerospace EngineeringSurface Pressure FluctuationsAerodynamicsComputational AcousticsAir Mobility Noise
A 63×63 rotative array was used to map cross‑power spectral densities of wall pressure fluctuations, and a novel post‑processing technique converted space‑frequency data into wavenumber‑frequency spectra to separate acoustic and aerodynamic loads, with the acoustic component estimated via a Corcos‑like model. The acoustic contribution was found to be only 5 % of the aerodynamic surface pressure fluctuations under automotive‑relevant conditions, indicating that both acoustic and aerodynamic loads must be considered for car interior noise.
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.
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