明渠恒定均匀流机械能损失构成分析  

Constitution of Mechanical Energy Loss of Steady Uniform Flow in Open Channel

作　　者：范敏[1,2] 朱远乐[3] 江耀祖[1] 王智娟[1] 

机构地区：[1]长江科学院水力学研究所,武汉430010 [2]重庆交通大学内河航道整治技术交通行业重点实验室,重庆400074 [3]长沙矿山研究院有限责任公司金属矿山安全技术国家重点实验室,长沙410012

出　　处：《长江科学院院报》2017年第6期67-71,共5页Journal of Changjiang River Scientific Research Institute

基　　金：国家重点研发计划项目(2016YFC0402004);重庆交通大学内河航道整治技术交通行业重点实验室开放基金项目(NHHD-201507)

摘　　要：明渠水流机械能损失的确定是水力学乃至工程流体力学中的重要内容。从明渠均质不可压缩液体恒定总流出发,以流体力学中黏性流体运动数学模型为基础,本质上揭示了机械能损失的构成和相互转化关系。成果表明:矩形明渠均匀流紊流的机械能损失由时均流速梯度引起的损失与紊动能耗散引起的损失组成,当雷诺数较小时,时均流速梯度引起的损失是机械能损失的主要来源,而雷诺数较大时,紊动能耗散引起的损失是机械能损失的主要来源。在宽浅明渠中,雷诺数约为9.5×103时,均流速梯度引起的损失和紊动能耗散引起的损失相等。The calculation of mechanical energy loss of flow in open channel is an important part both in hydraulic and fluid mechanics.In this paper the mechanical energy loss is obtained based on the viscous fluid model and the equation of total flow of constant homogeneous incompressible fluid in open channel.The constitutions of mechanical energy loss and their mutual transformation are revealed.Result shows that the mechanical energy loss are resulted from time-averaged velocity gradient and dissipation of turbulent kinetic energy.When the Reynolds number is small,the time-averaged velocity gradient is the main cause of mechanical energy loss;whereas when the Reynolds number is large,the dissipation of turbulent kinetic energy is a major contributor.In conclusion,in shallow and wide open shallow with a Reynolds number of 9.5×10~3,the mechanical loss caused by time-averaged velocity gradient is equal to that caused by kinetic energy dissipation.

关 键 词：矩形明渠 恒定均匀流 机械能损失构成 流体力学 紊动能耗散 时匀流速梯度 

分 类 号：TV133[水利工程—水力学及河流动力学]