小宽深比U型弯道环流试验研究

发布时间：2019-06-20 12:38

【摘要】：采用多普勒超声测速仪(ADV),对小宽深比的U型弯道沿程断面上各不同垂线位置上的点进行了三维流速测量,并基于所测数据分析了主流线位置、横向流速沿垂线分布、环流结构以及环流强度等水力特性。研究结果表明:在60°断面后,水流的表层与底层主流线开始分离,形成复杂螺旋结构。水流进入弯道后,沿程各断面均形成一逆时针主环流,并且从75°断面开始,凹岸表层又出现与主环流方向相反的次生环流;环流强度最大值位置出现在弯道弯曲度1/3处附近。研究结果为进一步深入研究弯道水流紊动特性和泥沙运动提供了有效参考。
[Abstract]:The Doppler ultrasonic velocimeter (ADV), is used to measure the three-dimensional velocity at different vertical positions along the section of U-shaped bend with small aspect ratio. Based on the measured data, the hydraulic characteristics such as the position of the main streamline, the distribution of transverse velocity along the vertical line, the circulation structure and the circulation intensity are analyzed. The results show that after 60 掳section, the surface layer of the flow begins to separate from the main streamline of the bottom layer, forming a complex spiral structure. After the water flow enters the bend, an inverse time needle main circulation is formed along each section, and from the 75 掳section, the secondary circulation opposite to the main circulation direction appears on the surface of the concave bank, and the maximum circulation intensity appears near 1 鈮，

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