基于平均紊动结构下明渠水流流速分布研究  

Velocity Distribution within Open Channel Studied Using the Average Structure of Turbulent Flow

作　　者：刘晓东[1] 韩宇 邱流潮[1] 于洋[2] LIU Xiaodong;HAN Yu;QIU Liuchao;YU Yang(China Agricultural University,Beijing 100083,China;Tsinghua University,Beijing 100084,China)

机构地区：[1]中国农业大学,北京100083 [2]清华大学,北京100084

出　　处：《灌溉排水学报》2018年第8期106-114,共9页Journal of Irrigation and Drainage

基　　金：国家自然科学基金青年科学基金项目(51509248);中国农业大学基本科研业务费专项资金项目(2015QC025;2017SL001);"十三五"国家重点研发计划项目(2016YFC0400200;2017YFC0403203)

摘　　要：【目的】揭示明渠水流外区域流速分布偏离传统对数定律的潜在机理。【方法】基于猝发现象,根据雷诺纳维-斯托克斯方程推导出了描述明渠水流流速分布的改进模型,并通过多组试验工况对改进模型的准确性进行了验证。【结果】(1)该模型的分析结果与明渠中内/外区域的流速分布均吻合较好,仅有1.1%左右的误差;(2)将试验结果与当前应用较为广泛的YL、ML和CL定律对比,这些定律预测的结果与外层区域的实测数据相比分别存在3.1%、4.5%、5.2%左右的误差。【结论】二维均匀流中存在尾流定律的原因来自于流速的上下紊动,这种紊动造成外区水流的流速微降。【Objective】The objective of this paper is to disentangle the underlying mechanisms that the distribution of water velocity in the outer region of open channel deviates from the log-law.【Method】We developed a new analytical model, similar to the Reynolds ＇average Navier-Stokes equations, by considering the bursts, and then verified it against experimental data.【Result】（1）The results calculated from the proposed model agreed well with the measured velocity distribution in both internal and outer regions of the channel with an error of 1.1%.（2）Compared with experimental velocity distribution, the errors resulted from the commonly used YL, ML and CL law in the literature were 3.1%, 4.5% and 5.2% respectively, much higher than the error of the proposed model.【Conclusion】The underlying mechanisms of the wake law in 2 D uniform channel flow is the result of up-down events, and such a turbulent flow slightly reduced the velocity in the outer region of the open channel.

关 键 词：流速分布 明渠 湍流 对数定律 猝发现象 

分 类 号：TV131.2[水利工程—水力学及河流动力学]