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Noise of the Harrier in vertical landing and takeoffThe noise of the Harrier AV8C aircraft in vertical takeoff and landing was measured 100 feet to the side of the aircraft where jet noise dominates. The noise levels were quite high - up to 125 dB overall sound level at 100 feet. The increased noise due to jet impingement on the ground is presented as a function of jet height to diameter ratio. The impingement noise with the aircraft close to the ground was 14 to 17 dB greater than noise from a free jet. Results are compared with small-scale jet impingement data acquired elsewhere. The agreement between small-scale and full-scale noise increase in ground effect is fairly good except with the jet close to the ground. It is proposed that differences in the jet Reynolds numbers and the resultant character of the jets may be partially responsible for the disparity in the full-scale and small-scale jet impingement noise. The difference between single-jet impingement and multiple-jet impingement may also have been responsible for the small-scale and full-scale disagreement.
Document ID
19890001485
Document Type
Conference Paper
Authors
Soderman, Paul T. (NASA Ames Research Center Moffett Field, CA, United States)
Foster, John D. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1988
Publication Information
Publication: The 1987 Ground Vortex Workshop
Subject Category
ACOUSTICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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