ISBN 9783843942003

978-3-8439-4200-3, Reihe Ingenieurwissenschaften

Benjamin Arnold
Wind Turbine Noise Reduction by Means of Boundary Layer Suction

213 Seiten, Dissertation Universität Stuttgart (2019), Hardcover, A5

Zusammenfassung / Abstract

Flow-induced noise represents one of the main hindrances of the onshore wind energy expansion. Detailed field measurements revealed turbulent boundary-layer trailing-edge noise to be the main contributor to wind turbine noise. Besides diverse passive noise reduction approaches among the research community, the fundamental mechanism of distributed boundary-layer suction to reduce trailing-edge noise has been numerically and experimentally demonstrated at the University of Stuttgart Institute of Aerodynamics and Gas Dynamics. However, the investigations mainly concentrated on the consideration of a wind-turbine-relevant airfoil and proof about the suction effectiveness in a realistic three-dimensional environment is still pending. The present work is meant to fill this gap and, hence, shall contribute to an increasing acceptance of wind turbines by residents and a maximization of installable power.

The latter shall be achieved by a transfer of the portrayed fundamental noise reduction potential of boundary-layer suction to full-size wind turbines. In order to provide guidance for this transfer, the present work introduces a method for the design of a boundary-layer suction system on full-size wind turbines that is divided into five crucial design steps. The suction system design method is first applied to the generic ’National Renewable Energy Laboratory’ 5 MW turbine. Properly designed, the suction system is capable of improving both the aerodynamic and aeroacoustic performance of the turbine. However, notwithstanding the auspicious results, the generic character of the considered turbine hitherto renders the outcome insensitive to industrial requirements or constraints, respectively.

In order to involve realistic boundary conditions for the design of the suction system, the method is further applied to the state-of-the-art industrial N117 wind turbine making use of previously derived design guidelines. Despite taking into account restrictive industrial constraints, the proven potential from the two-dimensional framework as well as the generic wind turbine carries over to the industrial application: With the promising potential of boundary-layer suction to reduce wind turbine noise demonstrated, the present work aims at providing the initial step towards a practical implementation and calming the oftentimes great hesitation towards active flow control approaches.