[ABSTRACT] In addition to the overall noise level, periodic variations in the loudness of wind turbine noise, known as Amplitude Modulation (AM), also significantly contribute to the annoyance experienced by residents living near wind farms. Due to the high dependence of AM on meteorological conditions and the type of wind turbines, the level and duration of AM are hard to predict. These characteristics have an important impact on the annoyance response of residents. The level of annoyance is expected to depend on the AM depth, the number of AM occurrences and the AM continuity. The aim of this paper is to investigate AM characteristics in the vicinity of two wind farms in South Australia. It has been found that to successfully quantify tonal AM based on the Reference Method proposed by the UK Institute of Acoustics, removing the A-weighting, changing the range of band-pass filter frequency and reducing the prominence ratio are also necessary. AM density at night-time is much higher than at day time (25% versus 15%). However, there is not significant difference between AM depth at night-time and day time. Furthermore, AM is more likely to occur when the wind turbines are operating significantly below their maximum rated power.
Duc-Phuc Nguyen, Kristy Hansen
College of Science and Engineering
Adelaide Institute for Sleep Health
Flinders University, Bedford Park, Adelaide, SA, Australia
Download original document: “Characterizing tonal amplitude modulation of wind farm noise” (22 MB)
This material is the work of the author(s) indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.
The copyright of this material resides with the author(s). As part of its noncommercial effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Send queries to query/wind-watch.org.
|Wind Watch relies entirely
on User Funding