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The acoustic field of a point source in a uniform boundary layer over an impedance planeThe acoustic field of a point source in a boundary layer above an impedance plane is investigated anatytically using Obukhov quasi-potential functions, extending the normal-mode theory of Chunchuzov (1984) to account for the effects of finite ground-plane impedance and source height. The solution is found to be asymptotic to the surface-wave term studies by Wenzel (1974) in the limit of vanishing wind speed, suggesting that normal-mode theory can be used to model the effects of an atmospheric boundary layer on infrasonic sound radiation. Model predictions are derived for noise-generation data obtained by Willshire (1985) at the Medicine Bow wind-turbine facility. Long-range downwind propagation is found to behave as a cylindrical wave, with attention proportional to the wind speed, the boundary-layer displacement thickness, the real part of the ground admittance, and the square of the frequency.
Document ID
19860060678
Document Type
Conference Paper
Authors
Zorumski, W. E. (NASA Langley Research Center Hampton, VA, United States)
Willshire, W. L., Jr. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 12, 2013
Publication Date
July 1, 1986
Subject Category
ACOUSTICS
Report/Patent Number
AIAA PAPER 86-1923
Distribution Limits
Public
Copyright
Other