急弯段水流能量输运与耗散特性试验研究  

THE EXPERIMENTAL STUDY OF THE CHARACTERISTCS ON FLOW ENERGY TRANSPORT AND DISSIPATION IN SHARPLY CURVED BENDS

作　　者：胡呈维 余明辉[3] 渠庚[1,2] HU Cheng-wei;YU Ming-hui;QU Geng(River Research Department,Yangtze River Scientific Research Institute,Wuhan,Hubei 430010,China;Key Laboratory of River and Lake Regulation and Flood Control in the Middle and Lower Reaches of the Changjiang River of Ministry of Water Resources,Yangtze River Scientific Research Institute,Wuhan,Hubei 430010,China;State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,Hubei 430072,China)

机构地区：[1]长江科学院河流研究所,湖北,武汉430010 [2]长江科学院水利部长江中下游河湖治理与防洪重点实验室,湖北,武汉430010 [3]武汉大学水资源与水电工程科学国家重点实验室,湖北,武汉430072

出　　处：《工程力学》2025年第4期253-264,共12页Engineering Mechanics

基　　金：国家自然科学基金项目(52009008,42006156,U2240224);武汉市知识创新专项基础研究项目(2023020201010112)。

摘　　要：急弯水流运动中,由于弯道环流与纵向流速之间存在着较强的非线性作用,弯道中水流能量输运与耗散规律与其在顺直河段中的情况也会存在显著差异,这将进一步影响弯道床面切应力的分布以及弯道河床冲淤变化。然而急弯水流能量输运及耗散机制尚未研究清楚。该文基于弯道水槽高精度三维试验数据,定量分析弯道水流动能转换中各因素所起作用的比重,然后与涡运动理论相结合,研究涡旋引起的能量耗散,定量分析不同的因素对于涡旋引起的能量耗散所起的作用。研究结果表明:弯道环流对时均动能的对流输运项的量级是各项中最大的,比其他项高一到两个数量级,显示了其在弯道动能输运过程中的主导地位;紊动能生成项量级在动能方程中最小,表明紊动场对时均流场动能的影响非常小,相比于环流影响可忽略不计;对于动能的耗散,时均流场离心力量级在拟涡能方程中最大,表明其对能量耗散的影响作用最大。研究结果还表明水流能量输运及耗散过程对弗劳德数的变化不敏感。研究成果有助于提高对水流能量输运及耗散完整过程的理解,加深对弯曲河道中由弯道环流产生的阻力的认识。In sharply curved bends,there is a nonlinear interaction between the streamwise velocity and the cross flow velocity,which leads to the adjustment of the flow energy transport,increasing the energy dissipation,and ultimately affecting the development of river bends.However,previous studies have not fully understood the mechanism of energy transport and dissipation in curved bends.In order to understand these mechanisms in depth,with the aid of detailed experimental data collected in a sharp open-channel bend,this study quantified the influence of key components in the kinetic energy equation and enstrophy equation.The results show that the component related to the transport of kinetic energy by cross-stream circulation is at least an order of magnitude larger than the other components in the kinetic energy equation,which contributes significantly to the redistribution of kinetic energy over the cross section.The component related to the production of turbulent kinetic energy in the kinetic energy equation shows the smallest order of magnitude and thus is almost negligible for the time-averaged flow field.Furthermore,over most of the measured area,the component related to the centrifugal force shows values of at least an order of magnitude larger than the other components in the enstrophy equation,which means that this component exerts the dominant influence on the energy dissipation.The results also revealed that the transformation process is insensitive to the variations in Froude number.These results are expected to improve the understanding of the complete process of energy transport and dissipation,especially the resistance caused by secondary flow in meandering rivers.

关 键 词：弯道环流 弗劳德数 水流能量 拟涡能 能量转化 

分 类 号：TV147[水利工程—水力学及河流动力学]