The importance of tip speed ratio on noise Pollution of H-Darrieus wind turbines

Noise pollution is a significant challenge in developing the use of wind turbines, especially in residential areas. H-Darrieus turbine is a wind turbine widely used in residential areas, usually exposed to variable wind speeds, and works in a wide range of tip speed ratios. In this article, the importance of tip speed ratio on the output power and noise pollution of an H-Darrieus turbine is numerically investigated using the SST-kω model (for flow simulation at tip speed ratios of 2.04 to 3.3) and the Ffowcs Williams-Hawkings equations (for noise calculation in far-field). The directivity results show that the angle position of maximum noise differs for different tip speed ratios. Therefore, noise calculation only at the angle position of 0o, widely used for wind turbines, is insufficient. The results show that in terms of noise pollution, tip speed ratios of 2.04 and 3.3 have the best and worst performances, with maximum noises of 67.91 dB and 71.85 dB, respectively. On the other hand, the tip speed ratio of 2.64 has the highest power (2.92 times the power of 2.04) with a maximum noise of 68.26 dB, which is negligibly higher than that for the tip speed ratio of 2.04. Overall, it is concluded that in terms of compromise between noise pollution and power generation, the tip speed ratio of 2.64 is the best point for this turbine.