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Supersonic propeller noise in a uniform flowThe sound field produced by a supersonic propeller operating in a uniform flow is investigated. The main interest is the effect of the finite forward flight speed on the directivity of the sound field as seen by an observer on the aircraft. It is found that there are cones of silence on the axis of the propeller. The semiapex angles on these cones are equal fore and aft of the propeller plane, and depend on the tip Mach number only. The Fourier coefficients of the acoustic pressure contain the Doppler amplification factor. The sound field weakens in the upstream direction and strengthen downstream. Kinematic considerations of the emitted Mach waves not only confirm these results, but also provide physical insight into the sound generation mechanism. The predicted zone of silence and the Doppler amplification factor are compared to the theoretical prediction of shock wave formation and the flight test of the SR3 propeller.
Document ID
19890044537
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Jou, Wen-Huei
(Flow Research Co. Kent, WA, United States)
Date Acquired
August 14, 2013
Publication Date
April 1, 1989
Publication Information
Publication: AIAA Journal
Volume: 27
ISSN: 0001-1452
Subject Category
Acoustics
Accession Number
89A31908
Funding Number(s)
CONTRACT_GRANT: NAS2-9807
Distribution Limits
Public
Copyright
Other

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