## Effect of wind shear on noise propagation

Can anyone recommend a source of information that quantifies how wind shear effects the propagation of sound/noise?

I know the basics in that wind shear either bends sound waves upwards or downwards but I'm looking for something that helps calculate the effect.
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 Quote by CWatters Can anyone recommend a source of information that quantifies how wind shear effects the propagation of sound/noise? I know the basics in that wind shear either bends sound waves upwards or downwards but I'm looking for something that helps calculate the effect.
Yes, Please see the following two Wiki pages for a few introductory remarks. To get intricate details of the mechanism, please see the three references shown.

"Wind shear can have a pronounced effect upon sound propagation in the lower atmosphere, where waves can be "bent" by refraction phenomenon. The audibility of sounds from distant sources, such as thunder or gunshots, is very dependent on the amount of shear."
http://en.wikipedia.org/wiki/Wind_shear

"Effects due to wind shear
The speed of sound varies with temperature. Since temperature and sound velocity normally decrease with increasing altitude, sound is refracted upward, away from listeners on the ground, creating an acoustic shadow at some distance from the source.[2] Wind shear of 4 m•s−1•km−1 can produce refraction equal to a typical temperature lapse rate of 7.5 °C/km.[5] Higher values of wind gradient will refract sound downward toward the surface in the downwind direction,[6] eliminating the acoustic shadow on the downwind side. This will increase the audibility of sounds downwind. This downwind refraction effect occurs because there is a wind gradient; the sound is not being carried along by the wind.[7]

5. Uman, Martin (1984). Lightning. New York: Dover Publications. ISBN 0-486-64575-4.

6. Volland, Hans (1995). Handbook of Atmospheric Electrodynamics. Boca Raton: CRC Press. p. 22. ISBN 0-8493-8647-0.

7. Singal, S. (2005). Noise Pollution and Control Strategy. Alpha Science International, Ltd. p. 7. ISBN 1-84265-237-0. "It may be seen that refraction effects occur only because there is a wind gradient and it is not due to the result of sound being convected along by the wind."
http://en.wikipedia.org/wiki/Speed_of_sound

Note: These data are typically used by environmental engineers while assessing sound propagation from noise sources that may pollute habitable spaces.

Cheers,
Bobbywhy

## Effect of wind shear on noise propagation

Thanks for that. I can see I'm going to have to take a trip to a good book shop.

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