Effects of Temperature-profile Variation on Refraction of Sound by Jet Flow

Effects of Temperature-profile Variation on Refraction of Sound by Jet Flow PDF Author: Jay C. Hardin
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ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 36

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Effects of Temperature-profile Variation on Refraction of Sound by Jet Flow

Effects of Temperature-profile Variation on Refraction of Sound by Jet Flow PDF Author: Jay C. Hardin
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 36

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NASA Technical Note

NASA Technical Note PDF Author:
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ISBN:
Category :
Languages : en
Pages : 628

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Refraction of Sound by Jet Flow and Jet Temperature Ii

Refraction of Sound by Jet Flow and Jet Temperature Ii PDF Author: E. Grande
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ISBN:
Category :
Languages : en
Pages : 0

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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).

Refraction of Sound by Jet Flow Or Jet Temperature

Refraction of Sound by Jet Flow Or Jet Temperature PDF Author: University of Toronto. Institute for Aerospace Studies
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 772

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Refraction of Sound by Jet Flow and Jet Temperature

Refraction of Sound by Jet Flow and Jet Temperature PDF Author: E. Grande
Publisher:
ISBN:
Category : Jet plane sounds
Languages : en
Pages :

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Publications in Acoustic and Noise Control from NASA Langley Research Center During 1940-1979

Publications in Acoustic and Noise Control from NASA Langley Research Center During 1940-1979 PDF Author:
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ISBN:
Category :
Languages : en
Pages : 110

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Publications in Acoustics and Noise Control from the NASA Langley Research Center During 1940 - 1974

Publications in Acoustics and Noise Control from the NASA Langley Research Center During 1940 - 1974 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 76

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The Aeronautical Journal

The Aeronautical Journal PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 612

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Monthly Catalogue, United States Public Documents

Monthly Catalogue, United States Public Documents PDF Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1730

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