Sound propagation from wind turbines under various weather conditions
2013 (English)In: 5th International Conference on Wind Turbine Noise, Denver, USA, 2013Conference paper (Refereed)
Continuous measurements of wind turbine sound were performed during approximately two years at two different sites in Sweden. Meteorological parameters were measured in parallel with the acoustical measurements to see the weather influence on the sound propagation. A combined effect of refraction (bending of sound ways) and ground properties was found. This meteorological effect starts to be important somewhere between 400 – 1000 m from a wind turbine and could give a meteorological variability of the expected sound level with 7 dBA during the summer and 14 dBA during snow cover conditions. A comparison between the wind turbine sound immission measurements, ISO 9613-2 and the recommended wind turbine sound propagation model in Sweden reveals that the models underestimate the highest sound levels. Sound propagation models in general need to consider the meteorological effect for better predictions at longer propagation distances.
During the half measurement period (one year) the sound level were stored 8 times per second to capture the amplitude modulation of the sound, which according to some, increases the annoyance. It was found that amplitude modulation roughly occurs 18 % of the time at a distance of 1 – 2 km from 12 wind turbines and is more common under specific meteorological conditions such as positive sound speed gradients and positive temperature gradients.
Place, publisher, year, edition, pages
Denver, USA, 2013.
Environmental Analysis and Construction Information Technology
IdentifiersURN: urn:nbn:se:uu:diva-210666OAI: oai:DiVA.org:uu-210666DiVA: diva2:663827
5th International Conference on Wind Turbine Noise
FunderSwedish Energy Agency, 32437-1