Experimental and theoretical studies are made of the spectra of noise and blade loading caused by interference of a propeller, helicopter rotor and fan rotor with inlet turbulence. Tests were made with hot-wire anemometers in a static inlet and pressure transducers on the blades of a fan rotor. It is found that the noise is partially coherent, with very narrow spectrum peaks. Spectrum peaks are explained by the narrow-band random mechanism of inflow turbulence and not as harmonic noise due to fixed inflow distortion.
Spectrum of rotor noise caused by atmospheric turbulence
Spektrum des durch atmosphaerische Turbulenz verursachten Drehfluegellaerms
Journal of the Acoustical Society of America ; 56 , 1 ; 110-126
1974
, 24 Quellen
Article (Journal)
English
FLUGZEUG , LAERM , ANEMOMETER , SCHALLDRUCK