Prediction of Flow-Induced Noise Sources of Wind Turbines and Application Examples

Abstract

The consideration of aeroacoustic aspects and the minimization of noise emission is an integral part in the design process of modern onshore wind turbines. In the present paper dedicated aeroacoustic prediction methods are introduced that are applied at the University of Stuttgart for identification of noise sources and the aero-acoustic design and analysis of airfoils and rotors of wind turbines. The available portfolio of tools ranges from fast semi-empirical methods to numerical CAA schemes with substantial computational demands. The chain of tools thereby enables a separation and quantitative comparison of the different relevant noise sources. Based on dedicated wind tunnel measurements of noise sources and noise emission of airfoils the methods have been continuously verified and improved. Besides a summary of the theoretical basis, specific validation examples are given that show the strengths and the deficiencies of the available methods and motivate ongoing improvements. Finally, application examples with practical relevance and means for a passive and active noise reduction are discussed.