Impact of Suction on Boundary-Layer and Noise Emission of Wind Turbine airfoils
A. Wolf, Th. Lutz, W. Würz, O. Stalnov and E. Krämer, DEWEK-2010, Bremen, 17-18 November, 2010
Wind farms can not be located too close to inhabitant regions due to prohibitive levels of noise emission. The noise emitted from operating wind turbines can be divided into two sources: mechanical, and flow-induced. In this study we are interested in attenuating flow-induced noise, particularly the dominant noise source generated due to turbulence - trailing edge interaction. The noise is generated by pressure fluctuations caused by the turbulence in the boundary layer which are scattered at the trailing edge of the turbine blade. Currently noise reduction is achieved by shape design  or other passive devices like serrated trailing edge. A candidate technology for further reducing the noise levels resulting from turbulent structures interacting with the trailing edge is Active Flow Control (AFC). Flow control techniques affect the boundary layer features and as such it can be expected that also the emitted trailing edge noise will be affected. Currently, numerical and experimental investigations are performed to investigate the effect of AFC on the boundary layer and their potential for trailing edge noise reduction.