Apparatus for measuring the absorption of sound by noise in one dimension.

Download
Author
Dorff, Stephen J.
Date
1991-12Advisor
Denardo, B.C.
Larraza, A.
Atchley, Anthony A.
Metadata
Show full item recordAbstract
A travelling wave tube for the study of high intensity acoustics has been constructed.
The tube has inner diameter two inches and length 70 feet, and consists of seven 10 foot long
sections smoothly joined by collars and flanges. Attached to one end is a housing that contains
two JBL horn drivers connected to the tube by a "Y" adapter. An anechoic end termination
spans the length of the last section. The termination is made of steel wool of tapered density
distribution. Pulse reflection measurements yielded an absorption of 40 dB or greater for
frequencies of 500 Hz and higher. Reflected signals of the junctions were typically 40 dB down.
Linear attenuation measurements indicated no appreciable acoustic losses at the junctions. Sum,
difference and second harmonic generation measurements revealed that interactions were
occurring in the medium of interest (air) and were not the result of the drivers or
intermodulations of the two drivers. The performance under these preliminary tests indicates
that the apparatus is suitable for nonlinear acoustics investigations.
Collections
Related items
Showing items related by title, author, creator and subject.
-
Warfare Innovation Workshop, "Unmanned Maritime System Life Cycle Costs" (archived)
Consortium for Robotics and Unmanned Systems Education and Research (CRUSER) (Monterey, California: Naval Postgraduate School, 2015-03);The Warfare Innovation Workshop (WIW) will be held 24-26 March at the Naval Postgraduate School as part of "Enrichment Week". The WIW will focus on Unmanned Maritime System (UMS) Life Cycle Costs. The goal of the workshop ... -
Highly absorbing metal nanolaminates for bi-material THz sensors
Apostolos, Karamitros (Monterey, California. Naval Postgraduate School, 2011-09);The terahertz (THz) region of the electromagnetic spectrum covers frequencies ranging from approximately 100 GHz to 10 THz. This region of the spectrum has not been fully utilized due to the lack of compact and efficient ... -
Managing Driving After Suspension: Non-Highway Safety Suspended Drivers
Eger, Robert J.; Brien, Spencer T. (2015);The objective of this study is to explore crash occurrences for drivers with suspension/revocation for nonhighway safety reasons. Using a sample of suspended drivers in eight states, results indicate that as a group, ...