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A Study Of Acoustic Disturbances And Means Of Suppression In Ventilated Transonic Wind Tunnel Walls
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Book Synopsis A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls by : N. Sam Dougherty
Download or read book A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls written by N. Sam Dougherty and published by . This book was released on 1977 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of acoustic disturbances and means of suppression from ventilated transonic wall samples was performed in a low-background-noise research tunnel at AEDC. Configurations for ventilation investigated were longitudinally slotted walls, with and without baffles in the slots, slats versus round rods, and perforated walls with normal or inclined circular holes with varied hole sizes and varied diameter/wall thickness ratio. Comparative acoustic data were acquired over a broad range of subsonic Mach numbers. Several of these wall configurations were found to emit intense, discrete whistling noise with overall root-mean-square amplitudes as large as five percent of the free-stream dynamic pressure. In all cases except one, suppressed noise levels not exceeding 0.75 percent of the free-stream dynamic pressure were achieved compared to a background noise level for the tunnel of approximately 0.47 percent with solid test section walls. Noise suppression was accomplished by means of appropriate devices added to the wall samples which could have application to actual transonic wind tunnel test sections. (Author).
Book Synopsis A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls by : N. S. Dougherty
Download or read book A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls written by N. S. Dougherty and published by . This book was released on 1977 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls by : N. S Dougherty (Jr)
Download or read book A Study of Acoustic Disturbances and Means of Suppression in Ventilated Transonic Wind Tunnel Walls written by N. S Dougherty (Jr) and published by . This book was released on 1977 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of acoustic disturbances and means of suppression from ventilated transonic wall samples was performed in a low-background-noise research tunnel at AEDC. Configurations for ventilation investigated were longitudinally slotted walls, with and without baffles in the slots, slats versus round rods, and perforated walls with normal or inclined circular holes with varied hole sizes and varied diameter/wall thickness ratio. Comparative acoustic data were acquired over a broad range of subsonic Mach numbers. Several of these wall configurations were found to emit intense, discrete whistling noise with overall root-mean-square amplitudes as large as five percent of the free-stream dynamic pressure. In all cases except one, suppressed noise levels not exceeding 0.75 percent of the free-stream dynamic pressure were achieved compared to a background noise level for the tunnel of approximately 0.47 percent with solid test section walls. Noise suppression was accomplished by means of appropriate devices added to the wall samples which could have application to actual transonic wind tunnel test sections. (Author).
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1982 with total page 1282 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.
Book Synopsis An Experimental Investigation of Techniques to Suppress Edgetones from Perforated Wind Tunnel Walls by : N. Sam Dougherty (Jr.)
Download or read book An Experimental Investigation of Techniques to Suppress Edgetones from Perforated Wind Tunnel Walls written by N. Sam Dougherty (Jr.) and published by . This book was released on 1975 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP. written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Journal of the Acoustical Society of America by :
Download or read book The Journal of the Acoustical Society of America written by and published by . This book was released on 1977 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of the Acoustic Characteristics of a Variety of Slot Baffle Configurations for Transonic Wind Tunnel Walls by : N. S Dougherty (Jr)
Download or read book An Experimental Investigation of the Acoustic Characteristics of a Variety of Slot Baffle Configurations for Transonic Wind Tunnel Walls written by N. S Dougherty (Jr) and published by . This book was released on 1979 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: A parametric study of various slot baffle geometric configurations was performed in an effort to find an improvement to the acoustic characteristics of baffled slotted walls used in the NASA/Ames Research Center transonic wind tunnels. The desired improvement was to reduce the aerodynamic noise generated by these walls. Parameters studied were baffle inclination angle, shape, and depth. A modification to wall samples which effectively suppressed the noise generated by the baffled slots was a fine-mesh wire screen overlay in combination with baffle inclination angle. The degree of tunnel was noise suppression achieved in the experiments was a factor of six less than the configuration now in use.
Book Synopsis Influence of Wind Tunnel Noise on the Location of Boundary-layer Transition on a Slender Cone at Mach Numbers from 0.2 to 5.5 by : N. Sam Dougherty (Jr.)
Download or read book Influence of Wind Tunnel Noise on the Location of Boundary-layer Transition on a Slender Cone at Mach Numbers from 0.2 to 5.5 written by N. Sam Dougherty (Jr.) and published by . This book was released on 1980 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to investigate the effects of wind tunnel test section noise on the location of boundary-layer transition. The study was carried out by conducting experiments on a slender, highly polished cone with an included angle of 10 deg. Wind tunnel test section noise was measured by microphones flush-mounted on the cone surface. In most of the experiments, boundary-layer transition was measured with a surface-mounted, traversing pitot pressure probe. The experiments were conducted in 23 different subsonic, transonic, and supersonic wind tunnels over a Mach number range from 0.2 to 5.5 and a unit Reynolds number range from 1.0 to 7.0 million per foot, the bulk of the data being obtained between 2.0 and 4.0 million per foot. The results show an influence of wind tunnel noise on boundary-layer transition for most of the wind tunnels. (Author)
Book Synopsis Influence of Wind Tunnel Noise on the Location of Boundary-layer Transition on a Slender Cone at Mach Numbers from 0.2 to 5.5 by : N. Sam Dougherty
Download or read book Influence of Wind Tunnel Noise on the Location of Boundary-layer Transition on a Slender Cone at Mach Numbers from 0.2 to 5.5 written by N. Sam Dougherty and published by . This book was released on 1980 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to investigate the effects of wind tunnel noise on the location of boundary-layer transition. The study was carried out by conducting experiments on a particular slender, highly polished cone having an included angle of 10 deg. Wind tunnel noise levels were measured in the test section by flush-mounted microphones imbedded in the cone surface. The measurement of boundary-layer transition location was made using either a traversing pitot pressure probe in contact with the cone surface or the flush-mounted microphones. The experiments were carried out in 23 different subsonic, transonic, and supersonic wind tunnels over a range of Mach numbers from 0.2 to 5.5 and a unit Reynolds number range from 1.0 to 7.0 million per foot, the bulk of the data being obtained for a range from 2.0 to 4.0 million per foot. The results clearly show a strong influence of wind tunnel noise on boundary-layer transition location correlatable with overall root-mean-square noise levels. Because the noise level generally varied with Mach number and unit Reynolds number, the unit Reynolds number was found to have little effect on transition Reynolds number. (Author).
Download or read book Aeronautical Engineering written by and published by . This book was released on 1993 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1977-12 with total page 1140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Suppression of Perforated Wall Noise in a Transonic Wind Tunnel and the Effects on Aerodynamic Data by : J. L. Jacocks
Download or read book Suppression of Perforated Wall Noise in a Transonic Wind Tunnel and the Effects on Aerodynamic Data written by J. L. Jacocks and published by . This book was released on 1978 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tests were conducted to determine the effect of screen overlays installed on the airside test section walls for the purpose of suppressing the wall noise. Data are presented to illustrate that the screens and resulting noise reduction affected the test section logitudinal flow uniformity, plenum-stream calibration, wave cancellation properties of the walls, transition Reynolds number, and shock/boundary-layer interaction. In general, the effect of noise reduction on viscous phenomena was similar to that observed with decreased Reynolds number.
Book Synopsis An Experimental Investigation of Techniques to Suppress Edgetones from Perforated Wind Tunnel Walls by :
Download or read book An Experimental Investigation of Techniques to Suppress Edgetones from Perforated Wind Tunnel Walls written by and published by . This book was released on 1975 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerodynamic noise emitted by perforated walls in transonic wind tunnels has been under study for several years at AEDC. This report presents a summary of recent experimental tests to suppress perforated wall noise in transonic test sections. The mechanism of noise generation from perforated walls having 60-deg inclined holes is the edgetone phenomenon where the shear layer over each hole interacts with the trailing edge to produce intense tones at discrete frequencies. Noise reduction was achieved with several modified wall samples in the 6-in. tunnel at resonance conditions.
Author :North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Symposium Publisher : ISBN 13 : Total Pages :452 pages Book Rating :4.E/5 ( download)
Book Synopsis Aerodynamics of Wind Tunnel Circuits and Their Components by : North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Symposium
Download or read book Aerodynamics of Wind Tunnel Circuits and Their Components written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Symposium and published by . This book was released on 1997 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Annual Index by :
Download or read book Government Reports Annual Index written by and published by . This book was released on 1979 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Collection of Technical Papers by :
Download or read book A Collection of Technical Papers written by and published by . This book was released on 1986 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
