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Wind farm noises: Mechanisms and evidence for their dependency on wind direction
The mechanisms responsible for swishing and thumping noises generated by wind turbines are unclear and the existence of which have significantly affected the perception of wind energy by the community. To better understand the nature of this noise source, this study, for the first time, investigates...
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Published in: | Renewable energy 2017-08, Vol.109, p.311-322 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The mechanisms responsible for swishing and thumping noises generated by wind turbines are unclear and the existence of which have significantly affected the perception of wind energy by the community. To better understand the nature of this noise source, this study, for the first time, investigates the correlation between the potential noise generation mechanisms in wind farms and the characteristics of the perceived noise reported by residents in the vicinity of the farms in survey data. Published reports and measurements show that in addition to the perceived noise near the turbines, the thumping noise, in general, is perceived far downstream of the turbines. Normal swish perceived in a short distance from a wind turbine, especially in the cross-wind directions, can be explained by the convective amplification and directivity of the trailing edge noise. As will be discussed in this article, there exists strong evidence that the dominant mechanism of wind farm noise is associated with amplitude modulation of the aerodynamic noise by the eddies generated when the turbine blade partially stalls or due to an interaction with the turbine wake. This hypothesis is primarily based on the low frequency characteristics of the stall and also the distance and direction of the noise propagation. Moreover, it is hypothesised that the wake supplements this effect as it results in refraction and modulation of the emitted noise.
•The perceived noise from wind farms and the possible noise generation mechanisms are linked to the directivity of the wind.•The wake acts as a conduit directing the noise energy downstream up to the point of the breakdown of the turbine wake.•It is concluded that the turbulent inflow as well as the partial or transient stall on the turbine blades are the main underlying mechanisms. |
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ISSN: | 0960-1481 1879-0682 |
DOI: | 10.1016/j.renene.2017.03.046 |