Australian study into wind turbine noise

ADELAIDE, Australia, June 1 (UPI) -- Australian acoustics researchers say they are investigating the causes of wind turbine noise with the aim of making them quieter.

Scientists at the University of Adelaide said wind turbines generate "trailing edge or airfoil noise," the same kind of noise generated at the edge of aircraft wings.

"We know generally what causes that noise -- as the turbulent air flows over the sharp edge of the blade it radiates sound much more efficiently, so the noise can be heard at some distance," Con Doolan of Adelaide's school of mechanical engineering said. "What we don't yet understand, however, is exactly how that turbulence and blade edge, or boundary layer, interact and how that makes the noise louder."

Complicating factors came from the effects when there are multiple wind turbines in the same area working together and the way the noise increases and decreases as the blades rotate, the so-called blade "swish" sound.

The researchers will use computer models to predict output from wind farms and their effect on the surrounding environment, a university release said Wednesday.

"Wind turbine noise is very directional," Doolan said. "Someone living at the base might not have a problem but 2 kilometers (1.2 miles) away, it might be keeping them awake at night."