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Forum Index : Windmills : Measuring wind turbine noise?

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Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5119

Posted: 05:07am 18 Jun 2009

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I've been asked what would be the correct way to measure a wind turbines noise level. Some wind turbines, as we know, have very noisy blades, and some dont. So how would you measure that noise level?

With the PVC blades on my F&P windmill, if I stand near the tower the only noise I can hear is the F&P Smartdrives whine, so I would consider the turbine to be silent under normal conditions. The tree's, about 10 meters away, are audible.

If I use a noise level meter, how would I measure the windmills noise if the trees are making more noise?

Hypothetical.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

vasi

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Joined: 23/03/2007
Location: Romania
Posts: 1697

Posted: 05:36am 18 Jun 2009

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Cutting the trees

?
I think a fair measure can be done in a quiet room,
spinning the propeller with something silent.

And depending on site. I think a measurement must be
done in a daylight, to see how noisy is a day in our
place, an then a night measurement... without having a
windmill installed... But I'm speaking about small
cities and villages where you can still have a windmill
and sound differences between day and night are
noticeable..

If windmill sound is covered by trees then is ok... if
there are no trees (to blame them) then what?

Edit:
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Oops! Konqueror browser is behaving like Chrome ...Edited by vasi 2009-06-19

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Robb
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Joined: 01/08/2007
Location: Australia
Posts: 221

Posted: 10:43am 18 Jun 2009

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I was thinking you'd need to set up the mill in an open field but then how do you stop the wind noise on the microphone. No wind no operation. Hmm the plot thinkens.

carl1
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Joined: 16/04/2007
Location: Australia
Posts: 79

Posted: 11:04am 18 Jun 2009

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Hi Glenn

I was working part in this field 35 years ago:

You need a kind of spectrum analyser recording the sound level with the windturbine switched off and another recording with the wind turbine running and then you substract the firt one from the second. The result shoud be the sound emission from the turbine running.
It's all on a logarithmic scale: like 3db more is two times the same sound pressure.

cheers
Harald

windlight
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Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 03:17pm 18 Jun 2009

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Refer to this site..
http://www.ccohs.ca/oshanswers/phys_agents/noise_measurement .html#_1_13

If one can hear it it's working (converted)

If one can see it it's objectionable mainly because the owner is getting something for free (non converted)

allan

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

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