针对垂直轴风力机固有的非定常流动特性，以及在小尖速比下存在动态失速的问题，进行了流场数值模拟研究。基于三点法，确定了垂直轴风力机叶片在尖速比为3.35、2.65、2.25和1.85下，不同周向位置处的有效攻角以及升、阻力系数等气动参数，并与名义攻角、多流管法获得的有效攻角进行对比。结果表明：垂直轴风力机在旋转过程中，叶片载荷呈周期性变化。三点法能够成功提取叶片在不同周向方位下计及诱导速度的有效攻角。随着尖速比的减小，叶片有效攻角变化幅度增加，叶片表面会在较早周向方位处发生流动分离，形成大尺度的旋涡结构，而且在下游时叶片还会受到上游尾流脱落涡的影响，使得叶片升、阻力系数等气动参数表现出更复杂的迟滞效应。

Aiming at the inherent unsteady flow characteristics of vertical axis wind turbine, and the problem of dynamic stall at small tip speed ratios, the numerical simulation of flow field is carried out. Based on the 3-Points method, the aerodynamic parameters such as effective angle of attack, lift and drag coefficients at different circumferential locations of vertical axis wind turbine blades at tip speed ratios of 3.35, 2.65, 2.25 and 1.85 are determined, and the similarities and differences are compared with those calculated by nominal angle of attack, and effective angle of attack by Double-Multiple Streamtube theory. The calculation results show that the blade load changes periodically during the rotation of vertical axis wind turbine. The 3-Points method can successfully extract the effective angle of attack of blades considering the induced velocity in different circumferential directions. With the decrease of the tip speed ratio, the change range of blade attack angle increases. The flow separation occurs on the blade surface in the early circumferential direction, forming a large-scale vortex structure. Moreover, the blade will be affected by the upstream wake shedding vortex at the downstream, which makes the aerodynamic parameters such as blade lift and drag coefficient show more complex hysteresis effect.