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Book Refraction of Sound by Jet Flow and Jet Temperature

Download or read book Refraction of Sound by Jet Flow and Jet Temperature written by E. Grande and published by Institute for Aerospace Studies, University of Toronto. This book was released on 1967 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Refraction of Sound by Jet Flow Or Jet Temperature

Download or read book Refraction of Sound by Jet Flow Or Jet Temperature written by J. Atvars and published by Institute for Aerospace Studies, University of Toronto. This book was released on 1966 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heart-shaped pattern of subsonic jet noise normally peaks somewhere between 15 degrees and 45 degrees from the axis, depending on conditions, falling off sharply as the axis is approached. Conflicting explanations of this directivity pattern appear in the literature. The present investigation suggests that the deep cleft in the pattern can be attributed mainly to refraction of the sound out of the jet by the velocity and temperature fields. The evidence lies in measurements made of the sound field of a harmonic 'point' source placed within a 3/4 in. dia. air jet. The source is the orifice of a tube about 1/16 in. i.d. driven through a conical coupling by a horn-type loudspeaker driver; this radiates sound essentially omnidirectionally up to about 15,000 cps. The experiment established the formation of an axial intensity minimum, which appears to be mainly due to refraction. The depth of the refraction valley increases with jet velocity, jet temperature, and sound frequency; a depth corresponding to an intensity reduction of the order of 35 dB is attained at M = 0.9 for 3000 cps. (Author).

Book Refraction of Sound by Jet Flow and Jet Temperature Ii

Download or read book Refraction of Sound by Jet Flow and Jet Temperature Ii written by E. Grande and published by . This book was released on 1966 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The refraction of the sound field of an omnidirectional pure tone 'point' source of sound by the temperature and velocity fields of a 3/4 inch air or nitrogen jet was measured. Several source positions were employed: one within the potential core, others entirely outside the jet. For the source in the on-axis position, the air jet velocity was varied between M = 0.5 and 0.95 at fixed source frequency and ambient jet temperature, yielding a characteristic axial refraction valley, e.g., -35dB at M = 0.95 and 3000 c.p.s. Similar, but asymmetric patterns were obtained with the source outside the jet. Using a very cold nitrogen jet (T = -180C), the sound was found to be refracted inward - a focusing effect - to yield an intensity lobe along the jet axis; e.g. +26dB at M = 0.11 and 7000 c.p.s. For both the cold jet and the ambient jet the ordinary jet noise was measured in narrow filter bands: the respective polar plots exhibited the same general shape near the axis as those for the injected pure tones. The filtered jet noise polar plots were also 'corrected' for refraction (using the pure-tone patterns) and for convection (via theory) to yield the approximate 'basic directivity' of the eddy sources: the polar patterns resemble ellipses of low eccentricity, rather unlike Lighthill's four-leaf-clover. (Author).

Book Refraction of Sound by Jet Flow Or Jet Temperature

Download or read book Refraction of Sound by Jet Flow Or Jet Temperature written by University of Toronto. Institute for Aerospace Studies and published by . This book was released on 1967 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Refraction of Sound by Jet Flow and Jet Temperature

Download or read book Refraction of Sound by Jet Flow and Jet Temperature written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Suppression of Refraction in Jet Noise by Cooling

Download or read book Suppression of Refraction in Jet Noise by Cooling written by J. T. Kelsall and published by . This book was released on 1975 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise generation in an air jet can be described in terms of a convection factor. The velocity gradients in the flow refract the sound, giving rise to a commonly observed final directivity. In the experiments outlined here the effects of convection and refraction on directivity are examined for a jet of very cold air. An attempt is made to determine whether any interdependence between convection and refraction can be detected experimentally in narrow band jet noise data. In the reported investigation liquid nitrogen was used to cool a jet of air (at nozzle speeds 0.21 to 0.28 of ambient sound speed) down to temperatures (between -110C and -155C) at which the refraction from the opposed velocity and temperature gradients produced cancellation effects.

Book Refraction of High Frequency Noise in an Arbitrary Jet Flow

Download or read book Refraction of High Frequency Noise in an Arbitrary Jet Flow written by and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Aerodynamically Generated Sound

Download or read book Aerodynamically Generated Sound written by H. S. Ribner and published by . This book was released on 1966 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is reported on six research projects as follows: Turbulence measurements relevant to jet noise; Role of refraction in jet noise; 'Basic' directivity and spectra of jet noise; Computer study of refraction of sound by jet flow and jet temperature; Pressure fluctuations on a plate with oblique jet impingement; Distortion of a shock wave traversed by a vortex; Acoustic energy flux from shock-turbulence interaction.

Book NASA Technical Note

    Book Details:
  • Author :
  • Publisher :
  • Release : 1975
  • ISBN :
  • Pages : 492 pages

Download or read book NASA Technical Note written by and published by . This book was released on 1975 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book UTIAS Technical Note

Download or read book UTIAS Technical Note written by and published by . This book was released on 1975 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Generation and Radiation of Supersonic Jet Noise  Theory of turbulence generated jet noise  noise radiation from upstream sources  and combustion noise

Download or read book The Generation and Radiation of Supersonic Jet Noise Theory of turbulence generated jet noise noise radiation from upstream sources and combustion noise written by and published by . This book was released on 1972 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book AERODYNAMICALLY GENERATED SOUND

Download or read book AERODYNAMICALLY GENERATED SOUND written by H. S. Ribner and published by . This book was released on 1964 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: Response of a flexible panel to turbulent flow: running wave versus modal density analysis; Turbulence measurements relevant to jet noise; An aerofoil probe for measuring transverse velocity in unsteady flow; Refraction of sound by jet flow and jet temperature; Distortion of a shock wave traversed by a vortex; and Survey article on jet noise.

Book Basic Aerodynamic Noise Research

Download or read book Basic Aerodynamic Noise Research written by Ira R. Schwartz and published by . This book was released on 1969 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 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 NASA Scientific and Technical Reports

Download or read book NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1967 with total page 2300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Generation and Radiation of Supersonic Jet Noise  Progress toward a unified theory of jet engine noise

Download or read book The Generation and Radiation of Supersonic Jet Noise Progress toward a unified theory of jet engine noise written by Lockheed-Georgia Company and published by . This book was released on 1972 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: