NASA Technical Reports Server (NTRS) 19920004539: Development and testing of cabin sidewall acoustic resonators for the reduction of cabin tone levels in propfan-powered aircraft : NASA Technical Reports Server (NTRS) : Free Download, Borrow, and Streaming : Internet Archive (original) (raw)
Publication date
Topics
NASA Technical Reports Server (NTRS), HELMHOLTZ RESONATORS, NOISE REDUCTION, PROP-FAN TECHNOLOGY, PROPELLER FANS, PROPELLER NOISE, RESONANT FREQUENCIES, SOUND GENERATORS, AIRCRAFT COMPARTMENTS, AIRCRAFT NOISE, EXCITATION, FLIGHT TESTS, FUSELAGES, TRANSMISSION LOSS, WALLS, Kuntz, H. L., Gatineau, R. J., Prydz, R. A., Balena, F. J.,
Collection
NASA_NTRS_Archive; additional_collections
Language
Item Size
154.4M
The use of Helmholtz resonators to increase the sidewall transmission loss (TL) in aircraft cabin sidewalls is evaluated. Development, construction, and test of an aircraft cabin acoustic enclosure, built in support of the Propfan Test Assessment (PTA) program, is described. Laboratory and flight test results are discussed. Resonators (448) were located between the enclosure trim panels and the fuselage shell. In addition, 152 resonators were placed between the enclosure and aircraft floors. The 600 resonators were each tuned to a propfan fundamental blade passage frequency (235 Hz). After flight testing on the PTA aircraft, noise reduction (NR) tests were performed with the enclosure in the Kelly Johnson Research and Development Center Acoustics Laboratory. Broadband and tonal excitations were used in the laboratory. Tonal excitation simulated the propfan flight test excitation. The resonators increase the NR of the cabin walls around the resonance frequency of the resonator array. Increases in NR of up to 11 dB were measured. The effects of flanking, sidewall absorption, cabin absorption, resonator loading of trim panels, and panel vibrations are presented. Resonator and sidewall panel design and test are discussed.
Addeddate
2016-09-28 14:49:19
Identifier
NASA_NTRS_Archive_19920004539
Identifier-ark
ark:/13960/t9f52kg41
Ocr
ABBYY FineReader 11.0
Pages
168
Ppi
600
Year
comment
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