【摘要】 为了分析明渠湍流中横向涡旋的尺度与动力学特征,利用自主研发的高频粒子图像测速系统测量了6种水流条件下的明渠恒定均匀流时间序列流场,使用涡旋提取方法识别涡旋,使用一套简洁客观的涡旋尺度及环量确定方法,分析了明渠湍流横向涡半径与环量的特征。涡旋的无量纲尺度与强度仅与所在位置有关,与雷诺数等其它因素均无关系。从壁面附近至对数区的上边界,涡旋的平均半径增大。受水面影响,半水深以上的涡旋半径有逐渐减小的趋势。在黏性作用下,涡旋的平均环量由壁面至水面总体呈减小趋势。时均剪切对逆向涡旋的尺度与强度均有抑制作用,其平均尺度与环量在全水深均小于正向涡。更多还原

【Abstract】 For analyzing the scale and dynamics characteristics of spanwise vortexes in open channel flows,instantaneous velocities were measured with high-speed PIV in steady uniform flow at 6 cases. Vortex extraction method was employed to identify vortexes and a simple and objective method was proposed to analyze the radii and circulation characteristics of spanwise vortexes. The scale and circulation of the vortex are only related to the location,and there is no relationship with the Reynolds number or other factors. The mean scale of vortex increases from near wall to the upper boundary of log layer. By the suppression of free surface,the vortex radius gradually decreases above half of the water depth. The average circulation of the vortex generally decreases from the wall to the free surface due to the effect of viscous. The scale and intensity of retrograde vortex are both inhibited by the mean shear,and its average radii and circulation are less than the prograde vortex in the full field.更多还原