The installation effects impose a distinct influence on the propeller noise characteristics. A simplified wing-propeller model with diverse installation positions were studied using unsteady numerical simulations to obtain the overall noise characteristics, component noise characteristics and key flow features under the take-off condition. The influence of installation locations on the propeller tone noise generation and radiation were analyzed. The results show that the installation effects lead to an increase of the thrust and maximum tone noise, and the direction of maximum tone noise moved upstream. The overlaid area between the propeller and the wing is the main region of wake-wing interaction, where the noise level is affected by Mach number, wake vorticity, wake-sweep region and so on. When the leading edge of the wing lies in the region with a horizontal distance of L = 0.5D and a vertical distance of H>0.3D, the installation effects can be weakened dramatically while the thrust can be still increased by 1%. The patterns of installation effect on propeller tone noise are identified from this research, which can be referred for low noise design of prop airplane.

Microphone phased array technique is an important measure for aeroacoustics research. In accordance with the difficulties of moving noise sources recognition, the core technology such as time domain beamforming algorithm and de-dopplerization methods were studied and the measurement technique of microphone phased array used for moving object was developed. The data processing algorithm is validated with the simulated noise source, as well as the influence of trajectory error and data length. In considering the loss of coherence due to atmospheric turbulence during propagation from noise sources on the aircraft to microphones on the ground, a kind of array optimization method was proposed to design the array suitable for UAV noise test. A flight test of UAV noise was carried out and the noise source of propeller and engine at take-off and low-altitude cruise were identified successfully.