Effect of the passive vortex generators on dynamic stall behaviors of the NREL phase VI blade under yawed inflow conditions

Passive vortex generators (VGs) are widely employed to mitigate flow separation on wind turbine blades. However, their efficacy under complex unsteady yawed conditions remains underexplored. This study investigates the dynamic stall characteristics of the NREL Phase VI blade controlled by passive VGs under yawed inflow using fully-resolved URANS simulations coupled with the transition model. The obtained results indicate that VGs effectively enhance the gross power coefficient by 1.9% under moderate yawed conditions by suppressing flow separation during high-angle-of-attack phases. However, this aerodynamic benefit diminishes significantly under severe yaw angles due to the dominance of deep stall and cross-flow. A critical finding is the spanwise disparity in dynamic stall topology. The rotation-dominated inboard sections exhibit anticlockwise lift hysteresis loops driven by centrifugal pumping, whereas the separation-dominated outboard sections display clockwise loops characteristic of vortex shedding. VGs function synergistically with Coriolis forces at the blade root to sustain high lift, while primarily fragmenting the separation bubble at the mid-span to delay stall onset. These findings clarify the complex interaction between VG-induced vortices and three-dimensional rotational augmentation, providing theoretical guidance for optimizing flow control strategies in realistic atmospheric environments.