Analysis of the wind turbine noise emissions and impact on the environment

Research of regularity patterns of statistic parameter variation of wind turbine (further referred to as WT) generated noise is presented in the article. The Fast Fourier Transform algorithm for the analysis of the measured data was used to establish the noise spectrum, which was a broadband range. In the noise spectrum, the greatest changes were observed in the frequency range of 200-5000 Hz when WT was operating and when it was not. The level of the wind turbine noise increases as wind velocity increases. But the level of this spectrum decreases under all frequencies when the distance from wind turbines increases. The literature data analysis reveals that the intensity level of WT generated acoustic noise depends on aerodynamic processes and mechanical noise intensity of its element flow. While estimating WT generated noise level, it is necessary to consider the background noise level evoked by wind, which significantly depends on wind flow velocity. When there are high wind speeds, WT generated noise is concealed by the background noise level evoked by wind. It was determined that WT generated noise level, when wind speed is v approximate to 12 m/s, and when there distance is greater than 100 m to the WT tower, it becomes equal to the background noise level. In such cases, the influence of WT noise on the environment could be underrated. Experimental and theoretical investigations of the WT generated acoustic noise were carried out. A methodology was developed, and a mathematical noise propagation model, which enables to forecast WT generated acoustic pollution level in residential places or other selected areas, was presented. (C) 2015 Elsevier Ltd. All rights reserved.