Wind farm noise amplitude modulation and its acceptability for sleep

Author: Duc Phuc Nguyen

Nguyen, Duc Phuc, 2019 Wind farm noise amplitude modulation and its acceptability for sleep, Flinders University, College of Science and Engineering

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Wind farm noise amplitude modulation (AM) is defined as a periodic variation in

the amplitude of the noise which occurs at the blade-pass frequency, which is a

unique characteristic of the noise. This phenomenon is a source of complaints due

to its potential to cause annoyance and sleep disturbance. Here, to analyse AM,

I proposed several modifications to the algorithm developed by the UK Institute

of Acoustics, which was developed only recently and is one of the best algorithms

available to date. I then used the modified algorithm to characterise the AM

measured at several locations near South Australian wind farms. To prepare stimuli

for laboratory experiments, I used the measured AM characteristics to synthesise

AM stimuli. During the experiment, AM was also investigated in terms of its level

of acceptability for sleep. I found that AM is audible both outdoors and indoors

up to several kilometres from a wind farm. Also, AM characteristics depend on

meteorological and operating conditions. The listening test results showed that

synthesised AM stimuli are indistinguishable from measured AM samples, indicating

that using synthesised noise for laboratory studies is suitable. Furthermore, I found

that an increase in the variation in the amplitude of the noise (AM depth) at a high

level of a tone (tonal audibility) is associated with lower acceptability for sleep for

noise-sensitive individuals. Further research is needed to understand the seasonal

and diurnal characteristics of AM and its effect on annoyance and sleep disturbance.

Keywords: Wind farm noise; Amplitude modulation; Acceptability for sleep.

Subject: Engineering thesis

Thesis type: Masters
Completed: 2019
School: College of Science and Engineering
Supervisor: Kristy Hansen