中文摘要：

本文采用Fluent软件对半径0．7m，翼型NACA4415的水平轴风力机的三维非定常尾迹流场进行了大涡模拟（LES）计算，计算结果表明：轴向速度分布相对于尾迹中心不对称，同一风速下，在靠近叶根圆周区域，距离风力机旋转平面2R处风力机轴向速度达到最小，由2R-3R区域逐渐过渡，然后增大最终恢复周围环境速度；而在靠近叶尖的圆周区域，在距风轮旋转平面1R处达到最小值，由1R-2R区域逐渐过渡，最终达到周围环境速度；中心涡对尾流影响的长度要大于叶尖涡对尾流长度的影响。尾流区不仅存在叶尖涡和中心涡，还存在叶片尾缘涡；低风速对尾流长度的影响要小于高风速。

英文摘要：

A large eddy simulation （LES） of the 3D unsteady flow field of the horizontal axis wind machine by Fluent Software was calculated in this paper and the wake of rotor radius was 0.7 m and airfoil was NACA4415. The calculation results showed that： the axial velocity distribution is asymmetry relative to wake center under the same wind speed, the axial speed of wind turbine becomes minimum far away from the wind machine rotating planar 2R place where near the hub circumference area, whereas it increased gradually at 2R- 1R area and regained the speed of surrounding environment eventually. However, in the region of nearing the tip circumference, the axial speed of wind turbine was minimum value which far away from the wind machine rotating planar 1R place, and changed gradually from 1R -2R area till reached the surrounding environment speed. Not only the tip vortex and the center vortex existed in the wake flow region but also the trailing-edge vortex.. Meanwhile, the effect on the wake of low wind speed was less than high wind speed.