The inflow shear and turbulence, tilt or yaw misalignment, and tower passage lead to dynamic stall on turbine blades. The effects of vortex generators (VGs) on the aerodynamic performance of a typical wind turbine airfoil, namely, DU91-W2-250, are measured under the background that VGs are gradually and widely installed for energy improvement. The experiment is carried out in a wind tunnel at the Reynolds number of 3 × 10 5. The oscillation of the testing model is driven by a servo motor, and the aerodynamic performance is measured using an ESP-64 scanner. The flow separation is visualized with tufts. The obtained results show that the installation of the VGs could effectively control both static stall and dynamic stall of the airfoil because VGs cause a lower pressure region on the airfoil suction surface near the leading edge and a pressure plateau that appears later than in the smooth airfoil. Meanwhile, the VGs could effectively increase the adverse pressure gradient and lead to an early transition to delay the flow separation before stall and force the flow field in the turbulence state. It is also found that the VGs could reduce the pressure fluctuations caused by the turbulence of the boundary layer during dynamic stall. Furthermore, the VGs are also found to be useful in suppressing the span-wise movement of vortices. However, the VGs could not improve the aerodynamic performance in the deep stall region under none of the static and dynamic conditions.

中文翻译：

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带涡流发生器的变桨距风力机翼型的实验研究

流入剪切和湍流、倾斜或偏航未对准以及塔架通道导致涡轮叶片动态失速。涡流发生器（VG）对典型风力机翼型 DU91-W2-250 气动性能的影响是在 VG 逐渐广泛安装以提高能量的背景下测量的。实验在雷诺数为3×10 5 的风洞中进行。测试模型的振荡由伺服电机驱动，气动性能使用ESP-64扫描仪进行测量。流动分离用毛簇可视化。结果表明，安装VGs可以有效地控制翼型的静态失速和动态失速，因为VGs在前缘附近的翼型吸力面上造成较低的压力区域，并且压力平台出现的时间晚于光滑翼型. 同时，VGs可以有效地增加逆压力梯度，导致提前过渡，延迟失速前的流动分离，迫使流场处于湍流状态。还发现VGs可以减少动态失速期间边界层湍流引起的压力波动。此外，还发现 VG 可用于抑制涡旋的展向运动。然而，