淹没状态下河道植物偏斜高度与糙率的关系

利用室内变坡水槽,模拟了复式河道滩地3种植物对漫滩水流的干扰作用,并借助声学多普勒测速仪(ADV)施测了不同垂线、不同测点的瞬时流速,计算了不同条件下的河道糙率。基于水动力及植物柔性变形分析,建立了淹没状态下的植物河道糙率计算的基本关系,反映出糙率值不仅与水流动力条件有关,还与植物类型、淹没高度、布置及其自身力学性能有关,同时,利用试验资料及理论分析成果,进一步获取了植物河道的附加糙率值,借此分析与评价河道植物对水流阻力的影响程度。

Relationship between height of vegetation after deflection and roughness coefficient of vegetated channels in submerged state

The influences of 3 kinds of vegetation planted in floodplain of compound channels on the overbank flow were simulated in a laboratory slope-variable flume.The instantaneous flow velocity at different measurement points along different vertical lines were measured with ADV,and the roughness coefficient of the river channel was calculated under different conditions.Based on hydrodynamic analysis and flexible deformation analysis of submerged vegetation,a formula for calculating the roughness coefficient of vegetated channels in submerged state was deduced,and the additional roughness coefficient of vegetated channels was obtained by means of the test data and result of theoretical analysis.Thus,the influences of vegetation on water flow in river channels were analyzed and evaluated.