A METHOD FOR CALCULATING THE FARFIELD BLADE/VORTEX INTERACTION NOISE

Abstract

A simple and efficient implementation of the FW-H method is presented, suitable for calculating the far-field blade/vortex interactions noise from rotors has been presented. The method is based on the FW-H formulation and makes use of surface pressure histories on the blades in order to evaluate the acoustic integral. The method is able to predict the Doppler shift and has been successfully used for BVI cases. More realistic comparisons between predictions and acoustic measurements will require to take into account, absorption from atmosphere, ground reactions and atmospheric turbulence. The method includes both thickness and impulsive noise contributions and only requires knowledge of the pressure distribution on the blades which may obtained from numerical aerodynamic calculation or experiments. The method is designed to take into account the rotation of the sound sources on the rotor blades. The formulation of the method are given.