A typical large industrial wind turbine affects the wind that blows upon it in two distinct ways. I apologize for the crudeness of the following drawings. Just as I'm not a qualified scientist, I'm also not a qualified artist ...
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Firstly, the turbine's support column produces a vertical 'wall' of variant air pressure downwind of itself ...
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 Secondly, the turbine's rotating blades produce a triple-coiled 'spiral' of variant air pressure downwind of themselves.
This effect is described here on the Danish Wind Industry Association's own website ... "In fact, there will be a wake behind the turbine, i.e. a long trail of wind which is quite turbulent and slowed down ... |
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I believe it's the angular impact of these two volumes of variant air pressure that produces sources of infrasound in the areas highlighted here in red .. sources located well behind the actual turbine ...
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Here is an aerial photo of an IWT complex that clearly shows the formation of air pressure variants or "turbulence wakes" (which, due to unique humidity conditions, have resulted in tell-tale localized "cloud formations" ...
 "Wake effect at Horns Rev wind energy facility, Denmark ... At wind farms where many towers are clustered together, turbulence generated by the massive blades can degrade the performance of other windmills by as much as 10-20 percent. The same turbulence can also trigger vibrations in turbines downwind, leading to component fatigue, excess maintenance costs, and premature part failure. The turbines' wake effect is clearly seen at the Horns Rev offshore wind farm in the North Sea west of Denmark." |
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Some of the recent investigations of the impacts of infrasound upon human health ...
2004 - Hearing at low and infrasonic frequencies - by H Moller, CS Pedersen, Department of Acoustics, Aalborg University, Denmark 2007 - Vibroacoustic disease: biological effects of infrasound and low-frequency noise explained by mechanotransduction cellular signalling. - by Alves-Pereira M, Castelo Branco NA., Lisbon, Portugal. 2008 - Wind Turbine Syndrome - by Doctor Nina Pierpont, Malone New York, USA 2008 - Tuning and sensitivity of the human vestibular system to low-frequency vibration. by Todd NP, Rosengren SM, Colebatch JG., University of Manchester, Manchester, UK. |
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These latest scientific findings are indicating that the distressing and harmful effects being reported from the proximity of industrial wind turbines come from infrasound they generate when in operation .. which appears to be impacting upon both physiological and neurological systems of the human body. |
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thewind.htm (January 26, 2009) |
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