Design of a boundary-layer suction system for turbulent trailing-edge noise reduction of wind turbines

• Published in: Renewable energy 2018-08, Vol.123, p.249-262
• Main Authors: Arnold, B., Lutz, Th, Krämer, E.
• Format: Article
• Language: English
• Subjects: Boundary-layer suction; Trailing-edge noise; Wind energy
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2018.02.050

The present work introduces a method for the design of a boundary-layer suction system for turbulent trailing-edge noise reduction of wind turbines. Since the latter hitherto has been primarily assessed in a two-dimensional framework, the paper is meant to point out whether the predicted improvements carry over to wind turbine flow. Since the processes of trailing-edge noise reduction and effective power alteration are intimately bound together, great emphasis is put on an accurate prediction of pump power requirement, the latter being based on a detailed suction hardware system implying pressure losses across each component. An exemplarily performed design reveals that, within a certain design regime, trailing-edge noise reduction is accompanied by an enhancement of rotor power. However, as of a distinct cross-over point at which the pump power requirement exactly compensates the amelioration of aerodynamic power, a trade-off between aeroacoustics and aerodynamics arises. The method bases on fully-resolved URANS computations and is applied to the generic NREL 5 MW turbine. •Boundary-layer suction system design for trailing-edge noise reduction of wind turbines.•Guidance is given through all relevant design steps.•Aerodynamics is predicted in the URANS framework, aeroacoustics with the acoustic code Rnoise.•Over a wide range of total mass flow rates, total trailing-edge noise reduction is coupled with an increase in rotor power.•As of a distinct cross-over design point, a trade-off between aerodynamics and aeroacoustics arises.