Anti-noise technique silences wind turbines
Environmental News Network: If wind energy converters are located anywhere near a residential area, they must never become too noisy even in high winds. Most such power units try to go easy on their neighbors' ears, but even the most careful design cannot prevent noise from arising at times: One source is the motion of the rotor blades, another is the cogwheels that produce vibrations in the gearbox. These are relayed to the tower of the wind turbine, where they are emitted across a wide area — and what the residents hear is a humming noise. "People find these monotone sounds particularly unpleasant, rather like the whining of a mosquito," says André Illgen, a research associate at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Dresden.
