Sound Source Identification Based on Conventional Beamforming and Its Application in the Wind Tunnel

Abstract:

Sound source identification based on beamforming is an important experimental method for the study of vehicle aerodynamic noise in wind tunnel. In order to better understand and apply this test technique， a series of simulation were conducted. The influence of factors such as array shape， source frequency， distance between array and testing object， and incidence angle of sound wave on the performance of the array was studied and validated with designed corresponding experiments. The results show that the increases of test distance and incidence angle will worsen the spatial resolution. As source frequency increases， the system spatial resolution becomes better， but the dynamic range worsens. As deviation of the distance between array and testing object increases， the identified source intensity decreases. Furthermore，the sensitivity of different source frequencies， testing distances， and array shapes to sound source amplitude errors caused by testing distance deviations varies. As the source frequency goes higher， testing distance becomes shorter， the sensitivity becomes higher accordingly. The mutual influence of multiple sound sources reduces the effective dynamic range of the array， while increasing the intensity of the sound sources. Afterwards， based on the full-scale DrivAer clay model， the sound sources distribution of the vehicle exterior was identified with beamforming array. Finally，the difference in sound source recognition results of rearview mirrors with different shapes was analyzed using the sound source subtraction method， which demonstrates that this technique can provide a powerful support for the development of vehicle wind noise.

Key words:vehicle wind tunnel;beamforming;sound source identification;sound source subtraction