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LEWY S CAPLOT M ONERA France
NOISE CERTIFICATION OF HELICOPTERS
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A-weighted acoustic acoustic mirrors Aeroacoustics Conference AIAA Paper aircraft noise altitude ANNEX 16 blade broadband noise calculated coherence computation core noise correction correlation cross spectrum dB(A duct Effective Perceived Noise emission EPNdB EPNL equation Figure flight path flow fluctuations flyover Fourier transform function harmonics helicopter noise helicopter rotor ICAO impulsive noise inlet interaction jet noise Journal of Sound low frequency Mach number main rotor maximum measurement point method microphone array NASA Noise Certification Noise Measurement noise sources nozzle obtained ONERA overflight parameters Perceived Noise Level PNLTM prediction pressure ratio procedure propagation propeller Propeller-driven Aeroplanes radiation reference conditions reference noise shock associated noise shock cell signal Sound and Vibration sound pressure level source image spectra subsonic technique temperature thickness noise tone noise transducers transonic true airspeed turboshaft turboshaft engine turbulence upstream velocity wave wind tunnel