Assessing and improving trailing-edge noise reduction technologies for industrial wind-turbine applications

Nowadays, large wind turbines are installed and operated close to densely populated areas due to the growing need for renewable energy. Noise constraints are hampering this development. The most relevant wind turbine noise source is the so-called Turbulent Boundary Layer Trailing-Edge (TBL–TE) noise. Many passive TBL–TE noise reduction technologies have been developed and tested in laboratories, yet only TE serrations are being implemented on real wind turbines. Some technologies, such as permeable TEs, have shown potential, according to wind-tunnel tests, to achieve higher TBL–TE noise reduction than the TE serrations. This thesis aims to advance the technological readiness level and industrial acceptance of the permeable TEs by maximizing their noise reduction capabilities while keeping their aerodynamic penalties limited. Design guidelines are derived based on both wind-tunnel aero-acoustic measurements and measurements of a real wind turbine featuring airfoil/blades equipped with a variety of TE noise reduction device prototypes