明渠恒定均匀流试验中尾门的影响范围

利用PIV测量了明渠恒定均匀流中离尾门（活页式及闸板式）不同距离的9条断面中垂线的流速分布,分析了尾门对中垂线时均流速、紊动强度、雷诺应力及能谱特征的影响范围。对比活页式和闸板式两种尾门的差异可以发现,闸板尾门对时均流速的影响要明显大于活页尾门,而对于脉动强度、雷诺应力和能谱特征的影响,二者差异可以忽略。对于时均流速,在距离50h后两种尾门的影响均小于1.0%;对于纵向紊动强度、垂向紊动强度及雷诺应力,以4.0%、4.0%、10.0%作为衡量标准,尾门的影响距离分别为35h、25h、30h;对于纵、垂向能谱特征参数k50,以偏差值15.0%、6.0%作为标准,尾门的影响距离分别为35h和40h。

Influence of tail gate on uniform open channel flows

Flume experiments were conducted to investigate the influence of tail gate（sluice gate versus louver-like gate）on the development of uniform open channel flows.Instantaneous velocities were measured by PIV at nine sections,and mean velocities,turbulent intensities,Reynolds stress and power spectrum of the mid-perpendicular were then calculated to evaluate tail gates’influence.Results indicate that the louver-like gate exerts a stronger influence on mean velocity than the sluice gate,while the difference of the two gates is negligible in their effects on other parameters.The existence of the gate causes a deviation of 1.0% on the mean velocity at the distance of 50h,4.0% at 35h on the longitudinal turbulence intensity,4.0% at 25h on the vertical turbulence intensity,10.0%at 30hon the Reynolds stress,15% at 35h on longitudinal power spectrum,and 5.0%at 50hon the vertical power spectrum.