中文摘要：

采用LES方法,对自行开发设计的100 W小型水平轴风力机在有、无风切变两种入流情况下的尾流特征进行了模拟计算,计算中提取了流场稳定后的x、y、z三个方向的瞬间速度、压力等参数的600个数据样本,计算得到了尾流内轴向速度和湍流强度的方均根值,分析了有、无风切变两种入流情况下风力机尾流内的时间平均轴向速度、湍流强度及涡结构等流动特征。结果表明：无风切变入流情况下,尾流内的叶尖涡、中心涡及轴向速度都呈现对称性;而风切变入流情况下,尾流内叶尖涡螺旋轨迹上面部分的螺距明显大于下面部分的螺距,呈现出了非对称性,而中心涡和轴向速度也都呈现出一定的非对称性,且风切变入流情况下尾流内的涡传播距离更远;在y/d〈6的近尾流区域内,无论入流是否存在风切变,风力机尾流膨胀现象都不很明显;在相同入流湍流强度条件下,有、无风切变入流情况下尾流内湍流强度的变化规律相似,入流风切变对尾流内湍流强度的影响较小。

英文摘要：

Large eddy simulation of 100 W wind turbine designed by ourselves is carried out in order to analyze and better understand the wake characteristic, such as time-average streamwise velocity, turbulence intensity and structures of vorticity, in shear and uniform inflow. In order to calculate the root-mean-squares of the streamwise velocity and the turbulence intensity, 600 data samples, such as instantaneous velocities and pressure in x, y and z direction, are taken over the last five rotations of the wind turbine blades. The results show that the tip vortex, the center vortex and the streamwise velocity are basically symmetrical without wind shear. When there is wind shear, the pitch of the tip vortex in the top is bigger than the pitch in bottom of the rotor disk, and the center vortex and the streamwise velocity are asymmetrical, and vortexes spread father. Regardless of wind shear, wind-turbine wake expansion phenomenon is not obvious at the y/d〈6. Under the condition of same inflow turbulence intensity, the changes of wakes turbulence intensity are similar with and without wind shear. In other words, wind shear has less effect on the wake turbulence intensity.