Aerodynamic Performanc and Aeroacoustic Characteristics of Model Rotor with Anhedral Blade Tip in Hover

Abstract

Experimental investigation on the aerodynamic performance and aeroacoustic characteristics of model rotors with different tip anhedral angles in hover are conducted in the paper. Three sets of model rotors with blade-tip anhedral angle 0°(reference rotor), 20° and 45° respectively are designed to analyze the influence of the anhedral angle on the hovering performance and aeroacoustics of rotor. In the environment of anechoic chamber, the hover experiments under the different collective pitch and blade numbers, are carried out to measure the figure of merit (FM), time history of sound pressure and sound pressure level (SPL) of the three rotor models. Based on test results, the comparison and analysis of hovering performance and aeroacoustic characteristics among the three rotor models have been done. Meanwhile, for the sake of analysis, the rotor wake and blade pressure distribution are simulated by means of computational fluid method (CFD). At last, some conclusions about the effects of blade-tip anhedral angle on the aerodynamic performance and aeroacoustic characteristics in hover are obtained. An anhedral blade tip can enhance the FM of the rotor, and decrease the rotor loads noise to some extent.