Difference between revisions of "Aeolian tones"

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<div class="definition"><div class="short_definition">Sound, usually in the [[band]] of audible frequencies, associated with wake-eddy, vortex-  produced [[pressure]] fluctuations resulting from air flow around obstacles, such as wires and twigs.</div><br/> <div class="paragraph">Although many such sounds are irregular noises, other familiar sounds involve fairly clear musical  notes or humming sounds. The latter sounds were called aeolian tones by Rayleigh. Their [[pitch]]  is controlled by the [[frequency]] with which [[eddies]] are formed and detached in the [[wake]] region  on the lee side of the obstacle. The tones produced by [[wind]] flowing over a cylinder, including  stretched wire, were shown by Strouhal in 1878 to be of frequency (pitch) ''f'' given by  <div class="display-formula"><blockquote>[[File:ams2001glos-Ae11.gif|link=|center|ams2001glos-Ae11]]</blockquote></div> where ''u'' is the cross-axis wind velocity (m s<sup>&minus;1</sup>) and ''d'' is the cylinder diameter (m).</div><br/> </div><div class="reference">Lord Rayleigh 1878. The Theory of Sound. Vol. II, . 412&ndash;413. </div><br/> <div class="reference">Humphreys, W. J. 1940. Physics of the Air. 3d ed., . 442&ndash;448. </div><br/>  
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<div class="definition"><div class="short_definition">Sound, usually in the [[band]] of audible frequencies, associated with wake-eddy, vortex-  produced [[pressure]] fluctuations resulting from air flow around obstacles, such as wires and twigs.</div><br/> <div class="paragraph">Although many such sounds are irregular noises, other familiar sounds involve fairly clear musical  notes or humming sounds. The latter sounds were called aeolian tones by Rayleigh. Their [[pitch]]  is controlled by the [[frequency]] with which [[eddies]] are formed and detached in the [[wake]] region  on the lee side of the obstacle. The tones produced by [[wind]] flowing over a cylinder, including  stretched wire, were shown by Strouhal in 1878 to be of frequency (pitch) ''f'' given by  <div class="display-formula"><blockquote>[[File:ams2001glos-Ae11.gif|link=|center|ams2001glos-Ae11]]</blockquote></div> where ''u'' is the cross-axis wind velocity (m s<sup>-1</sup>) and ''d'' is the cylinder diameter (m).</div><br/> </div><div class="reference">Lord Rayleigh 1878. The Theory of Sound. Vol. II, . 412&ndash;413. </div><br/> <div class="reference">Humphreys, W. J. 1940. Physics of the Air. 3d ed., . 442&ndash;448. </div><br/>  
 
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Latest revision as of 14:34, 20 February 2012



aeolian tones

Sound, usually in the band of audible frequencies, associated with wake-eddy, vortex- produced pressure fluctuations resulting from air flow around obstacles, such as wires and twigs.

Although many such sounds are irregular noises, other familiar sounds involve fairly clear musical notes or humming sounds. The latter sounds were called aeolian tones by Rayleigh. Their pitch is controlled by the frequency with which eddies are formed and detached in the wake region on the lee side of the obstacle. The tones produced by wind flowing over a cylinder, including stretched wire, were shown by Strouhal in 1878 to be of frequency (pitch) f given by
ams2001glos-Ae11
where u is the cross-axis wind velocity (m s-1) and d is the cylinder diameter (m).

Lord Rayleigh 1878. The Theory of Sound. Vol. II, . 412–413.

Humphreys, W. J. 1940. Physics of the Air. 3d ed., . 442–448.