Effect of Multi-nozzle Geometry on Jet-noise Generation
Author : Vern G. Rollin
Publisher :
Page : 17 pages
File Size : 34,85 MB
Release : 1961
Category :
ISBN :
Effect of Multiple-nozzle Geometry on Jet Noise Generation
Author : Vern G. Rollin
Publisher :
Page : 22 pages
File Size : 27,69 MB
Release : 1961
Category : Aerodynamics
ISBN :
Book Description
Effect of Multiple-nozzle Geometry on Jet-noise Generation
Author : VERN G. ROLLIN
Publisher :
Page : 1 pages
File Size : 46,50 MB
Release : 1961
Category :
ISBN :
Book Description
An experimental investigation was conducted in order to determine the effect of changes in the geometry of multijet nozzles on noise generation. Jet-pressure ratios of 1.67 and 2.33 were investigated for three-, five-, and seven-nozzle configurations with nozzle widths of 0.5, 0.75, 1.0, and 1.25 inches and spacings of 0.5, 1.0, and 1.5 inches. Test results showed that minimum power ratios were obtained at spacing ratios of 2.0 and 1.5 at subsonic and supersonic pressure ratios, respectively. Full-scale test results are in good agreement with the established curves. Significant reductions in the intensity of power-spectrum levels at the low- and midfrequency portions of the spectral distribution curve accompany a change in geometrical configuration of multiple nozzles to one with a minimum power ratio. (Author).
NASA Technical Note
Author :
Publisher :
Page : 458 pages
File Size : 43,68 MB
Release : 1961
Category :
ISBN :
Book Description
Investigation of Far Noise Field of Jets
Author : Edmund E. Callaghan
Publisher :
Page : 44 pages
File Size : 36,96 MB
Release : 1956
Category : Jets
ISBN :
Book Description
An investigation of the effect of nozzle shape on the noise generation of air jets was conducted on convergent (circular, square, rectangular, and elliptical), convergent-divergent, and several plug-type nozzles. The nozzle areas were approximately equal to the area of a 3- or 4-inch-diameter circular nozzle. At jet pressure ratios less than 2.2, all the nozzles had essentially the same sound field. At higher pressure ratios, only the convergent-divergentnozzle showed any appreciable reduction in sound power below that of an ordinary convergent nozzle. All nozzles showed discrete-frequency-type noises at high pressure ratios. The convergent-divergentnozzle eliminated such discrete frequencies when operated near its design point.
Effects of geometry and jet velocity on noise associated with an upper-surface-blowing model
Author : Lorenzo R. Clark
Publisher :
Page : 40 pages
File Size : 38,41 MB
Release : 1977
Category : Flaps (Airplanes)
ISBN :
Book Description
NASA Technical Memorandum
Author :
Publisher :
Page : 492 pages
File Size : 40,57 MB
Release : 1994
Category : Aeronautics
ISBN :
Book Description
Effects of Geometry and Jet Velocity on Noise Associated with an Upper-Surface-Blowing Model
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 36 pages
File Size : 10,62 MB
Release : 2018-08-09
Category :
ISBN : 9781724975348
Book Description
The noise characteristics associated with various upper surface blowing configurations were investigated using a small model consisting of a plate and flap assembly (simulated wing with flap) attached to a rectangular nozzle. Nozzle aspect ratio, flow-run length, and flap-deflection angle were the experimental parameters studied. Three nozzle-exit velocities were used. The normalized noise spectra obtained for different nozzle aspect ratios proved to be similar in terms of Strouhal number based on jet velocity and flow-run length. Consequently, the need for knowing local flow velocity and length scales (for example, at the flap trailing edge) as required in some of the existing noise prediction schemes is eliminated. Data are compared with results computed from three different noise prediction schemes, and the validity of each scheme is assessed. A simple method is proposed to evaluate the frequency dependence of acoustic shielding obtained with the simulated wing flap. Clark, L. R. and Yu, J. C. Langley Research Center NASA-TN-D-8386, L-11147 RTOP 505-03-11-04...
Experiments on High Bypass Internal Mixer Nozzle Jet Noise
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 24 pages
File Size : 42,75 MB
Release : 2018-07-20
Category :
ISBN : 9781723423468
Book Description
Model scale jet noise data are presented for a variety of internal lobed mixer nozzle configurations for take off power settings in a static environment. The results are presented for a 17.5 cm diameter fan nozzle to show the effect on noise levels caused by changes in geometric shape of the internal, or core flow, nozzle. The geometric variables include the lobe discharge angle, the number of lobes, spacing between the center plug and lobe valley, lobe side wall shape and axial contour of the lobes. An annular plug core flow nozzle was also tested and is used as a baseline for comparative purposes. Comparison of data from the internal lobed configurations showed that for comparative effect, in terms of the effect on full scale perceived noise levels, was caused by a change in the lobe discharge angle. The results showed that increasing the discharge angle caused an increase as large as 7 dB in sound pressure levels in the high frequency portion of the spectra. Changes in the other geometric variables cause negligible effects. Goodykoontz, J. H. Glenn Research Center NASA-TM-83020, E-1456, NAS 1.15:83020 RTOP 505-31-32
U.S. Government Research Reports
Author :
Publisher :
Page : 198 pages
File Size : 14,96 MB
Release : 1961
Category : Science
ISBN :
