The new exploration of noise source identifying in closed wind tunnel

Classical Beamforming arithmetic is the basic method for aero-acoustics test in wind tunnel. Many new optimization techniques up to date are developed based on it, for example CLEAN, NNLS (Non-Negative Least-Squares) and DAMAS (Deconvolution Approach for the Mapping of Acoustic Sources). But Classical Beamforming arithmetic has its own obvious shortcoming, which is that the resolving power of Classical Beamforming result is not high enough for both low frequency and high frequency signal. And especially when background noise exitsing, it has low Signal-Noise Ratio (SNR) due to background noise. A new method based on the classical Beamforming arithmetic is developed in this paper, which changes the width of beam by controling the phase of sound and varies the speed for beam focusing. The resolving power improves obviously for both low frequency and high frequency source when the method applied to noise source identifying. The skill of mechanism filtering is also proposed here. The filtering method is tending to reduce the effect of background noise by controlling the observation angle of microphone and improve the SNR of test.