Rotor blade-vortex interaction noise location and surface pressure in skew descending flight

Rotor Blade-Vortex Interaction (BVI) is the aerodynamic disturbance caused by rotors of the retreading side cutting the shedding vortex of the advancing side blade during the approach and departure of helicopters. Apart from exciting the blade surface pressure load, the interactions also sharply increase the rotor noise predominated by the BVI noise. This article first presents the numerical simulation of the rotor BVI load, followed by elaboration of the denoising method based on the period time synchronous averaging, the recognition and separation approach of the BVI noise from the rotor noise using wavelet decomposition reconstruction, and the noise location method based on bartlett time delay calculation and spherical interpolation. A rotor blade-vortex interaction noise test in the wind tunnel is designed and completed to verify these methods. We also develop the software applied to rotor BVI noise location and surface pressure test in skew descending flight status, and the research of the temporal and spatial relationship between the rotor BVI noise and blade surface pressure load. The main software interfaces, the vibration measurement system, and the modification method of noise source location aberrations are presented. The test results indicate that the rotor blade vortex interaction on the rotor disk mainly appears at the section of 310°-320° azimuth and 1.6-1.8 m radial position. © 2020, Beihang University Aerospace Knowledge Press. All right reserved.