TECHNIQUE FOR PROVIDING A SIGNAL FOR CONTROLLING BLADE VORTEX INTERACTION NOISE OF A ROTORCRAFT

摘要

A method of providing a signal representative of blade vortex interaction (BVI) noise for a multi-blade rotorcraft. The fluid (air) pressure at one, two, or more predetermined locations on a rotor blade is measured during at least one predetermined azimuthal segment of blade rotation during operation to provide respective pressure measurements. The pressure measurements are processed to provide a signal for use as a control variable in a control system for the active control of BVI noise. The pressure measurements are made within 10 % blade chord length of the blade leading edge and preferably two or more are made between 65 % and 95 % of blade radial-length. The pressure measurements are filtered and the band of retained frequencies is between 20 and 48 times the rotor rotation frequency. An algorithm operative over a determined blade frequency range optimizes the signal for control use.