RAY-ACOUSTICS APPROACH TO FUSELAGE SCATTERING OF ROTOR NOISE

A ray acoustics approach to fuselage scattering of rotor noise is cons idered based on a combination of classical geometrical acoustics and t he paraxial ray approximation. The method can handle scattering by obj ects of arbitrary shapes and can be applied in an inhomogeneous moving medium. Applications to aeroacoustics include the scattering of blade vortex interaction (BVI) pulses by rigid objects. The BVI is modeled by a rotating impulsive point force. It has been found that the scatte ring effects involving rotating sources cannot be ignored especially f or sideline noise. Application to tilt-rotors has also shown the impor tance of the scattering effects by rectangular fuselages.