Comparative Noise Measurements at Serrated and Porous Trailing-Edge Modifications

The presentation summarizes the outcome from recent measurements in the Acoustic Wind-Tunnel Braunschweig (AWB), conducted within the framework of the German wind energy project BELARWEA. Several modifications of the trailing-edge region of two different 2D airfoils were acoustically evaluated. The noise reduction potential of slotted, microperforated and serrated trailing-edge modifications are compared at varying test velocities, angles of attack and boundary-layer transition regions. The limitations of current trailing edge noise measurement setups are discussed in depth and a tentative interpretation of noise reduction mechanisms of serrations vs. alternative noise reduction technologies is provided