Accession Number ADA571107
Title Attenuation of Cavity Bay Noise.
Publication Date Oct 2012
Media Count 50p
Personal Author D. G. MacManus
Abstract This report concludes the investigation into the attenuation of cavity bay noise conducted under EOARD Award number FA8655-11-1-3025. A preliminary report was provided to EOARD in April 2012 and can be considered in conjunction with this final report. This investigation covers the experimental analysis and the development of passive palliative devices at both 1/40th and 1/20th scale and under both subsonic and supersonic conditions. Two methods of attenuation are of interest. The first is a resonant array based on the principle similar to that of a Helmholtz resonator and the second is a device comprised of a porous wire mesh coupled with a confined backing volume. The resonant arrays provide a source of viscous losses which can be targeted at the frequencies of the Rossiter modes within the cavity and the porous mesh devices provide viscous losses over a broader range of frequencies.
Keywords Aerodynamics
Attenuation
Cavities
Cavity acoustics
Foreign reports
Helmholtz equations
Military aircraft
Noise
Subsonic characteristics
Supersonic characteristics
United kingdom
Viscosity


 
Source Agency Non Paid ADAS
NTIS Subject Category 46A - Acoustics
Corporate Author Cranfield Univ. (England). School of Engineering.
Document Type Technical report
Title Note Final rept. 1 Sep 2011-31 Aug 2012.
NTIS Issue Number 1315
Contract Number FA8655-11-1-3025

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