王浩, 袁强, 孟震, 龚家国. 基于高速摄像技术的推移质运动特征试验[J]. 水科学进展, 2016, 27(6): 849-857. DOI: 10.14042/j.cnki.32.1309.2016.06.007
引用本文: 王浩, 袁强, 孟震, 龚家国. 基于高速摄像技术的推移质运动特征试验[J]. 水科学进展, 2016, 27(6): 849-857. DOI: 10.14042/j.cnki.32.1309.2016.06.007
WANG Hao, YUAN Qiang, MENG Zhen, GONG Jiaguo. Experimental study of bed load movement characteristics based on high speed video measurement[J]. Advances in Water Science, 2016, 27(6): 849-857. DOI: 10.14042/j.cnki.32.1309.2016.06.007
Citation: WANG Hao, YUAN Qiang, MENG Zhen, GONG Jiaguo. Experimental study of bed load movement characteristics based on high speed video measurement[J]. Advances in Water Science, 2016, 27(6): 849-857. DOI: 10.14042/j.cnki.32.1309.2016.06.007

基于高速摄像技术的推移质运动特征试验

Experimental study of bed load movement characteristics based on high speed video measurement

  • 摘要: 在明渠中开展不同水流条件下低强度均匀沙平衡输沙试验,基于灰度相减方法分析整个床面推移质运动特征,以探寻紊流结构与推移质运动之间的作用机理。结果表明:①受水槽横向方向水流强度分布特征影响,推移质运动概率从水槽中线到两侧壁逐渐变小,且基本呈对称分布;②在紊流相干结构作用下,推移质床面在紊流低速条带区形成凸槽,高速条带区形成凹槽,推移质运动概率沿水槽横向方向存在高低相间的带状分区;③随摩阻雷诺数增大,相邻两推移质运动高概率区域的间距值变化范围为0.13~0.24倍水槽宽度,其值随摩阻雷诺数增大而增大;④不同水流条件下,推移质运动高概率区域间距值约为水深的2倍,这与流向涡模型吻合,表明流向涡是诱导床面出现凹凸相间形态的重要因素。

     

    Abstract: Bed load transport is closely connected with the turbulent structures of open-channel flow. Studies on the interaction between the movement of sediment particles and flow turbulence are of essential significance to both fluid mechanics and river dynamics. Flume experiments with low equilibrium transport of uniform sediment at different flow conditions were conducted to study the mechanism of interaction between turbulence and sediment movement. The motion of particles on the whole bed were identified by examining the gray difference between the two successive images. Analysis of the measurements yields the following findings:① Influenced by the transverse distribution of flow intensity, the probability for sediment movement was symmetric transversely, reaching its maximum at the center and decreasing gradually toward the side wall; ② Under the influence of turbulent coherent structure, particles accumulated at the region of low-speed streaky structure and were scoured at the region of high-speed streaky structure. The probability for sediment movement exhibited high-and low-speed streaky regions alternatly in the z direction; ③ The increase of friction Reynolds number led to an increase in the interval of the nearby high sediment transport rate regions, ranging from 0.13 to 0.24 times as the width of flume; ④ Under different flow conditions, the values of D/H remained 2, which corresponded to the conceptual model of streamwise vortex, indicating that the structure of streamwise vortex was an important factor to the formation of the alternating concave and convex sediment structures.

     

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