Noise from wind farms may be more bothersome at night than it is during the day – and not only for the reasons you might expect.
While it’s true that competing sources of background noise (such as traffic) tend to die down at night, and people are more likely to notice sounds when they’re trying to fall asleep, scientists in Australia have found that physics as well as psychology plays a role in wind-farm-induced sleep disturbances.
According to Kirsty Hansen, an acoustics expert at Flinders University, one of the most noticeable types of wind farm noise is the “swooshing” sound produced as the blades rotate. In her latest research, published in Measurement and Applied Acoustics, Hansen and colleagues at Flinders and the University of Adelaide found that this swooshing sound (known technically as amplitude modulation, or AM) is by no means constant. “The noise seems to worsen after sunset,” explains Duc Phuc Nguyen, a PhD student at Flinders and the lead author of both studies. “We found that the amount of amplitude modulation present during the daytime versus night-time varies substantially, occurring two to five times more often during the night-time.”
Continue reading at https://physicsworld.com/a/wind-farms-get-noisier-at-night-say-phys...
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