Aeroacoustic phased array measurements in closed-section wind tunnel

As conventional viewpoint, aeroacoustic measurements require low background noise and minimal reflections for accurate results. So proper design of wind tunnel components and test apparatus are critical to successful aeroacoustic measurements. Over the past several years, microphone phased arrays have been developed based on sonar and radar technology. One of the biggest advantages is that the signal to noise ratio (SNR) is increased with the number of sensors in the array. This technology can be used to measure and identify the noise sources. It has been used in non-acoustic, hardwall wind tunnels, as a research tool to gain insight into noise and into the physical mechanisms causing the noise. Based on the frequency domain approach of beamforming algorithm, microphone phased array system has been developed by the author for aeroacoustic measurements in low speed closed-section wind tunnel. Array calibration and aeroacoustic measurements for a commercial aircraft were performed in FD-09 wind tunnel. The results indicated that array can identify the calibration resource accurately, and the availability of aeroacousitc measurement was validated by array calibration and application in low speed closed-section wind tunnel.