Print Email Facebook Twitter Noise studies from the fan-in-wing model Title Noise studies from the fan-in-wing model Author Krishnappa, G. Institution National Research Council Canada, National Aeronautical Establishment, Engine Section Date 1968-06-30 Abstract Some preliminary measurements of noise from a highly loaded fan-in-wing configuration are reported. Measurements of the spectra are presented for fan speeds of 7500, 9750, and 13,125 rpm (corresponding to tip Machnumber 0.35, 0.45, and 0.62) at an angle of 20º from the axis of the fan and at 5 feet from the inlet and efflux (aces of the fan. The experimental results show a discrete peak at blade-passing frequency, superimposed on a broad band noise that extends from 1000 cs to 15,000 cs. An analysis of the duet transmission of higher order modes at the above rotational speeds, as given by Tyler and Sofrin3), reveals high decay rates. This explains the absence of discrete tones at tbe harmonies of the blade - passing frequencies. The presence of high intensity broad band noise may be attributed to the turbulence in the wake and free stream turbulence ahead of the rotor blades. To reference this document use: http://resolver.tudelft.nl/uuid:c549901b-0b29-4e5c-bbb5-0c4bbafb4624 Publisher National Research Council Canada Access restriction Campus only Source National Research Council Aeronautical Report LR 508 Part of collection Aerospace Engineering Reports Document type report Rights (c)1968 National Research Council Canada Files PDF LR-508.pdf 3.07 MB Close viewer /islandora/object/uuid:c549901b-0b29-4e5c-bbb5-0c4bbafb4624/datastream/OBJ/view