连续弯道水流特性的试验研究

对正弦派生曲线生成的连续弯曲型河道开展试验,采用日本ACM2-RS型X-Y方向2轴电磁流速计对水流流速进行了测量,并对水流特性进行了分析。结果表明:连续弯曲河道纵向时均流速在弯顶处靠近凸岸处较大,而凹岸处较小,且沿河宽的分布沿程是变化发展的;弯顶水流纵向时均流速分布接近抛物线型,最大流速点位于上部水面以下,整体上大下小,而顺直过渡段水流纵向时均流速分布最大流速点位于底部,整体上小下大;连续弯曲河道水流阻力系数随着过水断面平均水深的增大而增大,随着过水断面宽深比的增大而减小。

Experiment study on flow characteristics of meandering river channel

An experiment is made on the meandering river channel in the form of the sine-generated curve; for which the flow velocity is measured with ACM2-RS 2D electromagnetic current velocity meter made in Japan and then the flow characteristic is analyzed. The experiment result shows that the longitudinal time-average velocity is larger near the convex bank and is less at the concave one，while the velocity distribution of the width of the river channel changes along the way. The profile of the longitudinal time-average velocity at the bending-top of the river channel is near a parabolic-type; meanwhile，the maximum velocity appears below the water surface and is larger to less from the upside to the downside generally. However，the maximum velocity of the longitudinal time-average velocity through the straight transition section of the channel appears near the river bed and is less to larger from the upside to the downside generally. The flow resistance coefficient of the meandering river channel increases along the increase of the average water depth and decreases along with the width-depth ratio of the flow cross-section.