有低矮植被覆盖的河道水流特性试验研究

通过室内水槽模型试验,探讨了有低矮植被生长的河道糙率变化、时均流速的垂线分布以及紊动强度的垂向变化规律.把植被区的垂向流速分布从河床表面到自由液面按有无植被的影响划分为3个区域,试验结果表明:时均流速垂线分布单调递增,增大到大于平均流速的某个值后达到稳定,之后流速分布为半对数分布;纵向、横向及垂向3个方向紊动强度最大值均出现在植被层顶部,且相同测点处存在T(x)>T(y)>T(z)的关系.经过试验分析认为:河道种植植被应选择远远处于淹没状态的较低矮的品种,且种植密度不宜太稠密,可起到固滩护岸、又不至于降低河道的泄洪能力的效果.

Experiment Research on Hydraulic Characteristics of Submerged Vegetation Channel Linings

By the indoor flume model experiment,the changing law of vertical velocity distribution and turbulent intensity of submerged vegetation channel linings are discussed.The velocity distribution inside and above the submerged vegetation can be divided into three zones from the bed surface to the water surface,The experiment results show that the mean velocity are increased humdrum,and then keep invariability,the velocity distribution reobey semi-logarithm distribution;The maximum of turbulent intensity in longitudinal,transversal and vertical orientation is presented at the top of vegetation,and T(x)>T(y)>T(z) in the same point.The analysises explain that far submerged,short vegetation should be choosen for river,and the planting density can not be too thick,it can strengthen the beaches and protect the banks,and the flood discharging result of channels doesn,t lower.