According to the simulations conducted by BST, the overall performance of wind turbines is increased due to applying riblets. They reduce turbulence and improve the performance of the blades by reducing the fluctuation velocity and the boundary layer thickness.
Two main problems with wind turbines are energy losses and increasing noise with rising wind speed. When modifying the blade surface with riblets, they not only counteract those problems by increasing power performance and reducing the noise, but also stable aerodynamics, increase lift, reduce drag and have a positive influence on the stall behaviour.
Since a wind turbine sees not only a variety of wind speeds but also different angles of attack, all considered riblet configurations need to be evaluated for different AoA not only in simulation, but also in a low speed wind tunnel for validation.
In Figure 2, the drag polars of different riblet configurations are being displayed. While they all show a similar curve, the configuration II-V01 (blue curve) seems to display the best results with the highest lift coefficient for the corresponding drag coefficient. The lift coefficients over drag coefficient change curves display a similar result (see Figure 3).