山区河流漂石阶梯阵列对水流结构影响的试验研究
Influence of Stepped Boulder Array on Flow Structure in Mountain River
作者：叶晨(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；张晨玲(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；张绍培(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；杨奉广(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)；王协康(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065)
Author：YE Chen(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；ZHANG Chenling(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；ZHANG Shaopei(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；YANG Fengguang(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)；WANG Xiekang(State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)
收稿日期：2017-09-04 年卷（期）页码：2018,50(1):36-42
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：山区河流;漂石阶梯阵列;流速分布;紊动强度
Key words：mountain river;boulder array;velocity distribution;turbulent intensity
基金项目：国家重点研发计划资助项目（2017YFC1502504；2016YFC0402304-1）；国家自然科学基金资助项目（51579163）
中文摘要
漂石阶梯阵列是山区流域暴雨山洪过程常见河床形式，能显著影响水流结构，增大水流阻力和河床抗冲力，同时也制约着漂石河床演变过程。基于野外典型漂石河段调查，通过水槽试验，探讨了山区河流漂石阶梯阵列河床的水动力特征。试验结果表明：不同的漂石阶梯行距对于水流流速及其紊动强度影响明显，三向紊动强度大体沿水深方向呈现先增大后减小趋势，横向与垂向的紊动强度峰值点位置都位于0y/h≤0.2水深处，近底逆流在垂向及主流方向的作用范围分别为1D与2D（D为漂石粒径），漂石下游的近底逆流作用范围与漂石粒径呈正相关。漂石阵列对近床湍流具有“均匀化”作用，随着漂石排列密度的增大可显著降低近底的紊动强度。
英文摘要
Stepped boulder arrays induced by flash flood are common riverbed forms in mountainous areas,and they can greatly affect the river flow structure and bed transformation.Although boulder arrays increase flow and river erosion resistance,they also stabilize river boundary and change the ability of the water to carry sediment,and therefore restrict the evolution of river bed.Based on the field investigation of typical riverbed and open channel experiments,the influence of stepped boulder array on flow structure with shallow depth conditions has been analyzed and discussed.All of the experiments were conducted on the fixed bed made of 4.0 cm plastic ball as model boulders.A side-view acoustic Doppler velocimeter (ADV) was equipped to record rapidly responding flow movement so as to analyze the flow turbulence.Our study showed that velocity and turbulence intensity were greatly affected by different spacing of stepped boulder arrays.Within the stepped boulder arrays,the turbulence intensities inu,vandwdirections increased first and then decreased and their peak points of the turbulence intensities invandwdirections were located at boulder downstream 0y/h≤0.2.The scale of far-wake region,which is mainly concentrated atxDarea in the longitudinal andh=1Din the vertical impact range of boulder,was positively correlated with the boulder size.The boulders arrays had a "uniform" effect on turbulence near the bed,and the increase of the spacing of stepped boulder arrays significantly reduced the turbulence intensity near bed.
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