Super-hydrophobicity effects on performance of a dynamic wind turbine blade element under yaw loads.

Flow characteristics over a dynamic section of wind turbine blade in the presence of super-hydrophobic coatings were studied numerically using computational fluid dynamics method. Assuming a super-hydrophobic coating, blade icing can potentially be prevented. Fluids on super-hydrophobic surfaces are moving; so slip velocity exists on their walls. The dynamic motion was in sinusoidal mode that caused deep dynamic stall (DS) phenomenon. The occurrence of DS results in enlarged vortices with high strength of vorticity. These vortices cause overshoot in aerodynamic loads. By applying a super-hydrophobic surface on different locations of the airfoil, the DS vortex generation can be definitely affected. Investigation of these effects, is the aim of this paper. There is no study in the literature that analyzed DS in the presence of slip velocities at different locations. Thus, an SD7037 airfoil was simulated at R e ≈ 4 × 10 4 using Transition-SST model. Results demonstrated that as the coating covered the leading edge, DS and vortex formation were postponed and the lift peak reduced about 10.6%; while for airfoil entirely covered by coating, the maximum lift value was augmented 14.6% and DS delayed. Applying slip boundary conditions at trailing edge as well as the pressure side had not considerable changes in cyclic loads. • In cold climates, wind turbine blades may be iced; blade icing can dramatically reduce performance. • A water-repellant surface can potentially prevent atmospheric icing on the blades. • Dynamic stall is a limiting phenomenon for designing horizontal axis wind turbines. • Turbine blade performance in the presence of super-hydrophobic surfaces during dynamic stall occurrence analyzed. • The location of coating had different results for cyclic loads. At the pressure side, no noticable effects were observed. [ABSTRACT FROM AUTHOR]