Download or read book A Study of Resonant cavity and Fiberglass filled Parallel Baffles as Duct Silencers written by Paul T. Soderman and published by . This book was released on 1982 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustical performance and pressure drop were measured for two types of splitters designed to attenuate sound propagating in ducts-resonant-cavity baffles and fiberglass-filled baffles. Arrays of four baffles were evaluated in the 7- by 10-Foot Wind Tunnel Number 1 at Ames Research Center at flow speeds from 0 to 41 m/sec. The baffles were 2.1 m high, 305 to 406 mm thick, and 3.1 to 4.4 m long. Emphasis was on measurements of silencer insertion loss as affected by variations of such parameters as baffle length, baffle thickness, perforated skin geometry, cavity size and shape, cavity damping, wind speed, and acoustic field directivity. An analytical method for predicting silencer performance is described and compared with measurements. Unlike small, single-orifice resonators, the undamped, resonant-cavity baffles attenuated sound over a broad frequency range. With the addition of cavity damping in the form of 25-mm foam linings, the insertion loss above 250Hz of the resonant-cavity baffles was improved 2 to 7dB compared with the undamped baffles; the loss became equal to or greater than the insertion loss of comparable size fiberglass baffles at frequencies above 250Hz. Variations of cavity size and shape showed that a series of cavities with triangular cross-sections (i.e., variable depth) were superior to cavities with rectangular cross sections (i.e., constant depth). In wind, the undamped, resonant-cavity baffles generated loud cavity-resonance tones; the tones could be eliminated by cavity damping. Duct-resonance tones were also generated by configurations that had solid skin over portions of the baffle surfaces. The effects of skin porosity, baffle length, and baffle thickness are documented. (Author).
Download or read book NASA Technical Paper written by and published by . This book was released on 1990 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Paper written by United States. National Aeronautics and Space Administration and published by . This book was released on 1990 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1982 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1982 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1983 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Scientific and Technical Publications written by and published by . This book was released on 1987 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1983 with total page 1050 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA86 1854 AIAA 86 1899 written by and published by . This book was released on 1986 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow induced Resonance of Screen covered Cavities written by Paul T. Soderman and published by . This book was released on 1990 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Scientific and Technical Publications written by and published by . This book was released on 1987 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sources Paths and Concepts for Reduction of Noise in the Test Section of the NASA Langley 4x7m Wind Tunnel written by and published by . This book was released on 1984 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technology written by James R. Ramsey and published by . This book was released on 1986 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications written by James R. Ramsey and published by . This book was released on 1986 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Architecture Series Bibliography written by and published by . This book was released on 1986 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Shock and Vibration Digest written by and published by . This book was released on 1981 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1982 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
