含非淹没植物明渠糙率系数及非均匀流水力特性

Roughness Coefficient and Non-uniform Flow Characteristics in Open Channel with Unsubmerged Vegetation

根据水力学对明渠水流流动类型的划分,提出按均匀流和非均匀流分别进行研究的新思路。通过对植物段上游水流和植物段水流的研究,得到种植植物后植物段上游形成M1型非均匀流,植物段基本形成M2型非均匀流,其相对水深随排列密度增大而增大,种植物前非均匀流水深越小,种植物后水深变化越大,植物段的相对糙率系数和相对水力坡度均随植物排列密度增加而增大,且植物横向加密比纵向加密糙率系数增加的快,阻水效果更明显等结论。

Based on the classification of the types for open channel flows, the studies for the uniform flow and non-uniform flow were performed in the experiments. The flows of upstream reach and vegetation reach were studied respectively. The results show that M1 non-uniform flow is formed in the upstream reach, and M2 non-uniform flow is formed in the vegetation reach basically after planting the rigid cylinders in the flume. The relative depth is increase with the increasing of cylinder density, and the lower the depth of the non-uniform flow before planting cylinders, the larger is the change of the flow depth after planting cylinders. Simultaneously, both the relative roughness coefficients and relative energy slopes are increased with the increasing of the cylinder density in vegetation reach, and the increasing of the cylinder density in transverse direction produces the higher roughness coefficients than that in longitudinal direction, thus the water-tight effect is more obvious.