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

Abstract

Abstract 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.