Research project: Spectral leading-edge serrations for the reduction of aerofoil-turbulence interaction noise

Wind turbine manufacturers also require new technology for the significant reduction of aerodynamic noise in order to make wind turbines more acceptable to communities, especially concerned with onshore wind farms. Such a technology breakthrough can only be achieved through a fundamental evaluation and re-design of aerofoils, particularly the "leading edges" (LE), since upstream turbulent flows impinging on the LE of an aerofoil is believed to be the dominant source mechanism of broadband noise in turbofan engines (rotor wakes scattered by the outlet guide vanes - OGV) and wind farms (upstream rotor wakes scattered by the downstream turbine blades). In turbofan engines, it is envisaged that new LE design would be applied to the OGV since noise reductions can only be achieved by modifying the OGV response or the rotor wake turbulence (much more difficult).

The EPSRC-funded research project aims to develop and investigate new aerofoil LE designs for the reduction of the broadband noise generated by the interaction between the aerofoil's LE and impinging turbulent flows, whilst minimising its impact on aerodynamic performance. The new aerofoil LE designs will be constructed by combining "smooth" spectral (wavy) serrations with multiple wavelengths, which has never before been attempted. In this project, a coordinated aeroacoustic and aerodynamic study of this new LE topology is proposed, particularly focused on the effects of smaller wavelengths (comparable to the impinging turbulence length scale), which are expected to be effective in reducing noise without making a significant impact on aerodynamic performance. The project will take full advantage of the experimental and computational expertise of the investigators. The successful outcome of this project will lead to a new aerofoil LE design that offers maximum noise reduction and minimum aerodynamic penalty. The commercial and academic impact of this work is potentially substantial.