Noise Management on Modern Wind Turbines

This paper describes the activities in which the wind turbine industry is taking part to reduce the noise emission. The produced noise could risk the development of this technology in populated areas and it has become one of the most important environmental impacts of wind energy. The turbulent nature of the incoming flow, the presence of the terrestrial boundary layer, the elastic deformations and the moving geometry makes the problem difficult to solve. In this context the reasonable alternative is to find semi-empirical methods that could be applied to reduce noise with the time constraints imposed by the market. The beginning of this paper introduces the most relevant noise sources for wind turbines and their theoretical treatment, then the description of the strategies that are used to reduce noise levels are discussed, and finally the current research projects where the industry is participating for noise reduction are presented.