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Jet noise modification by the 'whistler nozzle'The farfield noise characteristics of a subsonic whistler nozzle jet are measured as a function of Mach number (0.25, 0.37, and, 0.51), emission angle, and excitation mode. It is shown that a whistler nozzle has greater total and broadband acoustic power than an excited contraction nozzle; and that the intensity of far-field noise is a function of emission angle, Mach number, and whistler excitation stage. The whistler nozzle excitation produces broadband noise amplification with constant spectral shape; the broadband noise amplification (without associated whistler tones and harmonics) increases omnidirectionally with emission angle at all Mach numbers; and the broadband amplification factor decreases as Mach number and emission angle increase. Finally the whistler nozzle is described as a very efficient but inexpensive siren with applications in not only jet excitation but also acoustics.
Document ID
19840040568
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hasan, M. A. Z.
(Houston Univ. TX, United States)
Islam, O.
(Houston Univ. TX, United States)
Hussain, A. K. M. F.
(Houston, University Houston, TX, United States)
Date Acquired
August 12, 2013
Publication Date
March 1, 1984
Publication Information
Publication: AIAA Journal
Volume: 22
ISSN: 0001-1452
Subject Category
Acoustics
Accession Number
84A23355
Funding Number(s)
CONTRACT_GRANT: NSF MEA-81-11676
CONTRACT_GRANT: NAG3-198
Distribution Limits
Public
Copyright
Other

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