PROPELLER SOUND FIELD MODIFICATION SYSTEMS AND METHODS

摘要

A propeller system for an aircraft includes an assembly for modifying a sound field of the propeller system. The propeller system includes a rotor supported for rotation about a rotor axis. The rotor has a central hub and a plurality of blades each extending outwardly from the hub to a tip. The rotor and blades are operable to propel an aircraft to travel in a direction. The rotor blades define a rotor plane perpendicular to the rotor axis. The blade tips define a circumferential rotational path as the blades are rotated by the rotor. The propeller system includes an acoustic resonator or multiple resonators having openings disposed within a distance to the propeller blade tip that is small compared to the wavelength of the propeller's fundamental blade tone and proximate to the rotor plane. The resonators are excited by tip flow of the blade as it passes the opening. The acoustic resonators are configured and positioned so as to direct acoustic energy to modify the sound field of the propeller system at blade pass or higher harmonic frequency tones in a desired direction relative to the aircraft.

主权项

1. A method for modifying a sound field of a propeller system of an aircraft, the method comprising:
receiving data representing an acoustic profile of a propeller system of an aircraft; receiving real-time data indicating a propeller speed, orientation of the aircraft, and a weather condition surrounding the aircraft; determining a desired modification to the acoustic profile based on the received real-time data; and tuning an acoustic resonator to achieve the desired modification to the acoustic signature of the propeller system.