摘要
对淹没树状植被水流速度分布规律进行研究,建立了流速解析解模型,模型先将植被水流划分为树干层、树冠层和自由水层,然后将树干层再细分为近床面区和掺混区。研究结果表明,近床面区纵向速度垂向上接近定值;掺混区处于与树冠段交界处,水流紊动剧烈,纵向流速表现为随水深增加而降低。基于Boussinesq涡流粘度理论,采用二阶变系数线性微分方程求解方法,得到树冠层纵向流速垂向分布公式;该层流速与植被直径紧密相关,当植被直径增加时流速减少,当植被直径减少时流速增加。自由水层则直接引用经典对数律流速公式,流速与水深是对数关系。实验结果表明,模型计算值与实验测量值吻合良好,表明模型是合理有效的。
This paper presents a study of velocity distribution of water flowing through submerged vegetation with tree-like canopy,and establishes an analytical model of water flow velocity.The model first divides the water flow into stem layer,canopy layer and no-canopy layer,and then subdivides the stem layer into near-bed zone and blending zone.The results show that the longitudinal velocity in the near-bed zone is almost constant.The blending zone is at the junction with the canopy layer.The turbulence intensity in the blending zone is strong,and the longitudinal velocity reduces as the water depth increases.Based on the Boussinesq eddy viscosity theory,the vertical distribution of longitudinal velocity in the canopy layer can be derived by solving the two-order linear differential equation with variable coefficients.The water flow velocity at this layer is negatively correlated with canopy diameter.The velocity decreases with increment of canopy diameter,and increases with reduction of canopy diameter.In the no-canopy layer,the classical logarithmic formula is directly used because the relationship between velocity and water depth follows classical logarithmic law.The experimental results show that the calculated values of the new model agree well with experimental data,which indicates that the model is reasonable and effective.
作者
陈甜甜
赵明登
张颖
CHEN Tiantian;ZHAO Mingdeng;ZHANG Ying(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)
出处
《武汉大学学报（工学版）》
CAS
CSCD
北大核心
2020年第6期492-497,526,共7页
Engineering Journal of Wuhan University
基金
国家自然科学基金资助项目(编号:51479145)。
关键词
淹没植被
流速分布
分层水流
树状植被
圆柱绕流
submerged vegetation
velocity distribution
stratified water flow
vegetation with tree-like canopy
flow around a circular cylinder
