淹没柔性植被明渠恒定水流水力特性的试验研究  

Experimental study on hydraulic behaviors of steady uniform flow in open channel with submerged flexible vegetation

作　　者：槐文信[1] 韩杰[1] 曾玉红[1] 杨中华[1] 

机构地区：[1]水资源与水电工程科学国家重点实验室,武汉大学,湖北武汉430072

出　　处：《水利学报》2009年第7期791-797,共7页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(50679061,50709025,50749031)

摘　　要：采用三维多普勒超声测速仪(ADV)对淹没柔性植被明渠恒定水流的水力特性进行了试验研究。采用羽毛来模拟天然河道的柔性植被,对不同的植被密度、不同淹没度和不同流量条件下柔性植被明渠恒定水流流速场进行了测量,得到了淹没植被情况下纵向流速和雷诺应力沿垂向的分布。结果表明,植被上层区域与植被区域水流表现出不同的水力特性,植被上层区域的雷诺应力近似为直线分布,纵向流速呈经典的对数律分布;而植被区域,纵向流速则呈"S"型分布。在分析植被上层水流雷诺应力与纵向流速的关系的基础上,利用普朗特混合长度理论推导了植被上层水流流速的理论表达式,该公式的计算结果与实测数据符合良好。The 3-D acoustic Doppler velocimeter was applied to measure the steady uniform flow in open channel with submerged flexible vegetation in model test. The vegetation was simulated by using feathers. The 3-D flow velocity distribution for different vegetation densities, different flow depth-vegetation height ratios and flow discharge were measured and the vertical distributions of Reynolds stress of the flow were obtained accordingly. The experimental results show that the longitudinal flows in the depth over the vegetation and within the height of vegetation exhibit different hydraulic characteristics. The Reynolds stress of the flow over the vegetation is linearly distributed along the depth, and the distribution of velocity obeys the logarithmic law. Whereas, in the depth within the height of vegetation the longitudinal flow velocity exhibits S type distribution. On the basis of the analysis on the relationship between Reynolds stress and longitudinal flow velocity a theoretical expression for distribution of longitudinal velocity is deduced based on the Prandtle's mixing length theory. The formula is in good agreement with experimental data.

关 键 词：淹没柔性植被 混合长度 超声测速仪 雷诺切应力 纵向流速 

分 类 号：TV133[水利工程—水力学及河流动力学]