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Effect of flow on the acoustic performance of extended reaction lined ductsA model is developed for the effects of uniform and boundary-layer mean flow on the attenuation and propagation of harmonically excited sound waves in an extended reaction lined cylindrical duct. A duct geometry consisting of an annular outer region of bulk material surrounding an inner cylinder of air is utilized. A numerical solution is obtained for the coupled wave equations governing the motion of the sound in both the inner and annular regions. It is found that the numerically predicted attenuation and propagations constants are in excellent agreement with measured values using Kevlar as the liner material for plane-wave mode (O,O) excitation over a wide range of mean flows and sound frequency. The boundary-layer effects are determined to be unimportant, at least for plane-wave sound. In addition, numerical studies indicate small differences between the use of either the radial velocity or the radial displacement boundary conditions.
Document ID
19830046806
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Hersh, A. S.
(Hersh Acoustical Engineering, Inc. Chatsworth, CA, United States)
Walker, B.
(Hersh Acoustical Engineering, Inc. Chatsworth, CA, United States)
Date Acquired
August 11, 2013
Publication Date
April 1, 1983
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 83-0778
Meeting Information
Meeting: American Institute of Aeronautics and Astronautics, Aeroacoustics Conference
Location: Atlanta, GA
Start Date: April 11, 1983
End Date: April 13, 1983
Sponsors: American Institute of Aeronautics and Astronautics
Accession Number
83A28024
Funding Number(s)
CONTRACT_GRANT: NAS3-21975
Distribution Limits
Public
Copyright
Other

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