含沉水植物河道水流流速特性研究

在梯形平底水槽中，用塑料草模拟了沉水植物对水流的影响。结果表明：（1）流速不同、相对植物高度不同的情况下，植物对流速的影响是不同的；（2）含沉水植物的水流垂向流速分布曲线存在一条流速分界线，在其上部流速变大，下部流速变小，流速分界线在植物冠层以上，在相对水深h／H=0．3附近；（3）两株植物叶片之间是否有交叉重叠对水流的阻碍作用是有区别的；有交叉重叠时会额外增加水流阻力；在流速分界线以下，叶片有交叉重叠时流速减小幅度较大。

The research for the flow velocity characteristics in rivers growing marine plants

The plastic grass was used to simulate the impact of marine plants on flow velocity in trapezoidal channel with flat bottom.The results showed that:(1) the impact of the marine plants on the flow velocity is different,under the different relative plant height and different flow velocity;(2) the vertical velocity distribution curve has a certain dividing line,the flow is bigger above it,small below it;normally the dividing line located on above the plant canopy near the relative water depth h/H=0.3.(3) it is a difference if there is overlap between two leaves,duet to the overlap can decrease the flow and increases additional flow resistance;the flow margin reduced is larger below the dividing line.