Direct numerical simulations of aerodynamic performance of wind turbine airfoil by considering flap-wise blade oscillations

Aeroelasticity of modern wind turbines is a critical issue which can significantly affect the structural integrity and lifetime of the wind turbine blades. However, previous aeroelastic or aerodynamic studies were mostly concentrated on low-fidelity numerical methods, and the details of flow separation and vortex generation over wind turbine airfoils cannot be detected with these methods. In this study, a high-fidelity direct numerical model is used to investigate the details of flow separations and laminar separation bubbles (LSB) over a NACA-0012 wind turbine airfoil under oscillation. The simulations are conducted at Reynolds number of Re = 1.3 × 105 and the blade has harmonic pitch-wise oscillations at Mach number of Ma∞ = 0.4. Strong fluctuations are observed in the wake region of the vibrating wind turbine blade. The results show that the blade vibrations have a significant influence on vortex generation and separation point over wind turbine blades. details of flow structure over wind turbine blades compared to previously proposed models.