Aeroacoustic Analysis of Coaxial Rotor with Rotor-Fuselage Interaction

摘要

This study investigates the aeroacoustic characteristics of a coaxial rotor with rotor-fuselage interaction. Compared to the conventional single rotor, the coaxial rotor can satisfy higher aerodynamic performances and recently it is proposed for Unmanned or Personal Aerial Vehicles due to its advantages and improved performance. It is required to predict accurately the aerodynamic and aeroacoustic performances with various operating configurations. In this study, a numerical analysis was conducted to identify the aerodynamic and aeroacoustic characteristics of the coaxial rotor with rotor-fuselage interaction based on free wake vortex lattice method and Ffowcs-Williams Hawkings equation. The fuselage surface is consisted of Source and doublet panels to enable considering interaction with the wake and the rotor. We observed that the thrust of the coaxial rotor with fuselage is lower than that of the isolated coaxial rotor in case of the level flight. We also observed that the thrust fluctuation of the coaxial rotor with fuselage is higher than that of the isolated coaxial rotor. Although the coaxial rotor has its own unsteadiness, the fuselage has quite intensified the pressure fluctuations of the blade surface affecting the unsteady loading noise. As a result, the aeroacoustic characteristics (such as the amplitudes and directivities) of the coaxial rotor with fuselage differs significantly from the isolated coaxial rotor.