摘要
为研究浅滩植被对复式河道水动力特性的影响,了解植被作用下滩槽间水流动量交换的影响机制,利用Fluent流体力学仿真软件,选取标准的k-ε湍流模型封闭雷诺方程,对浅滩植被作用下的复式明渠内的流体运动特征进行精细化模拟,分析了不同淹没高度、不同流量条件下滩地植被对复式断面明渠的水流速度、湍流动能及断面二次流变化的影响。结果表明:受植被的影响,植物区计算主流速度的垂向分布不再呈对数分布,而呈现准S型的分布;相对无植被的工况,植物区内主流流速减小,随着滩地植被高度的增加,植物带的内部与上部区域主流速度减小,而主槽内主流流速相应增大,说明植物的存在对滩地区域的水流产生明显的阻碍作用,使断面主流向河道主槽内转移,植物的存在也对横向速度产生较强的扰动,能够促使断面二次流的形成;植物顶端附近的湍流动能变化较大,随着浅滩植被高度的增加,植被和水流交界处的湍流动能最大值也发生相应的变化,说明在植被顶端存在较大的动能交换;随着入流流量的增加,断面主流速度呈增大趋势,各测点湍流动能沿水深方向的幅值也相应增大。研究表明,Fluent流体力学仿真软件能够较好地精细化模拟滩地植被对复式河道水动力特性的影响,其计算结果可为河流防洪工程、河道浅滩整治及生态护岸等工程的实施提供科学依据。
In order to investigate the effect of the floodplain vegetation on the hydrodynamic characteristics in the compound open channel to understand of mechanism of hydrodynamic exchange in floodplain under vegetion,the fluid mechanics software(Fluent)was adopted to simulate the flow characteristics and to understand the flow momentum exchange between the floodplain and the main channel of the compound open channel in the presence of vegetation.The standard k-εturbulence model was chosen to close N-S equations in the Fluent software,and the influences of the floodplain plant on the velocity,turbulent kinetic energy and the secondary flow in the section of the compound open channel were analyzed under the conditions of different submerged vegetation heights and different inflow rates.It was found that the vertical velocity of main stream in vegetation region presented no more logarithmic distribution,with quasi“S”type distribution.The results showed that the velocity of the main stream in the vegetated area was decreased compared with that in absence of vegetation,with the increase in the vegetation height,and decrease in the vegetated region,while the velocity in the main channel was increased correspondingly.Thus the plants blocked the flow movement in the floodplain,and made the mainstream transfer to the main channel of the river.The plants in the floodplain made a disturbance for the transverse velocity and enhanced the formation of the secondary flow.In the vegetation area,the vertical change in turbulent kinetic energy near the top of the vegetation was violent,and the turbulent kinetic energy at the interface of vegetation was also changed significantly with the increase in the vegetation height in the floodplain,indicating that there was a large kinetic energy exchange at the top of vegetation.In addition,the velocity of main stream was increased with the increase in the inflow discharge,and the vertical turbulent kinetic energy was increased correspondingly.The findings indicate that Fluent software can w
作者
杨颖宜
李东子
马永顺
张明亮
YANG Yingyi;LI Dongzi;MA Yongshun;ZHANG Mingliang(College of Marine Science and Environment, Dalian Ocean University, Dalian 116023, China)
出处
《大连海洋大学学报》
CAS
CSCD
北大核心
2021年第2期317-324,共8页
Journal of Dalian Ocean University
基金
国家重点研发计划项目(2019YFC1407704)
国家自然科学基金(51879028)
辽宁省高等学校海洋产业技术研究院项目(2018-CY-19)。
