A comprehensive study by the UK’s Salford University has concluded that the noise phenomenon known as aerodynamic modulation (AM) is not an issue for the country’s wind farm fleet.
The government-commissioned work assessed 133 operational wind projects across Britain and found that although the occurrence of AM cannot be fully predicted, the incidence of it from operational turbines is low. AM – aerodynamic noise from wind turbines that is greater than the normal degree of blade swish – is sometimes described as sounding like a distant train or distant piling operation.
Out of all the working wind farms at the time of the study, there were four cases where AM appeared to be a factor, a result that the government does not consider constitutes a compelling case for doing more work on the phenomenon.
The research into aerodynamic modulation of wind turbine noise report by the University of Salford was jointly commissioned by three government departments and may be found at http://www.berr.gov.uk/files/file40570.pdf