中文摘要：

利用高频PIV系统对风力机下游远至4.5倍风轮直径范围内的尾流数据进行了采集。首先通过脉动速度均方根云图分析,发现中心涡轨迹区域内粒子脉动轴向速度均方根大于叶尖涡轨迹区域,而叶尖涡轨迹区域内粒子脉动径向速度均方根大于中心涡区域;然后对比1、2、3、4倍风轮直径处所有径向位置的脉动合速度均方根,发现叶尖涡的耗散速度比中心涡要快,所以叶尖涡轨迹区域脉动合速度均方根比中心涡轨迹区域减小得快,同时发现了叶尖涡＂交互跳跃＂现象。

英文摘要：

The wake stream data as far as 4.5 times of the rotor diameter in wind turbine downstream was collected by TR-PIV.Firstly,through analyzing the RMS nephogram,the axial RMS of the particles in the center vortex trajectory region is found greater than the axial RMS in the tip vortex trajectory region,but the radial RMS in the tip vortex trajectory region is found greater than the radial RMS in the center vortex trajectory region.Then comparing the resultant RMS in all radial position of the X/D=1,X/D=2,X/D=3,X/D=4（X represents the axial position,D represents the rotor diameter）,the dissipation speed of the tip vortex is found faster than the center vortex,so the resultant RMS in the tip vortex trajectory region decreases faster than the resultant RMS in the center vortex trajectory region.Meanwhile the ＂leapfrogging phenomenon＂ of the tip vortex is found.