| 引用本文: | 刘晓东,韩宇,邱流潮,等.基于平均紊动结构下明渠水流流速分布研究[J].灌溉排水学报,2018,37(8):106-114. |
| LIU Xiaodong,HAN Yu,QIU Liuchao,et al.基于平均紊动结构下明渠水流流速分布研究[J].灌溉排水学报,2018,37(8):106-114. |
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| 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。 |
| 关键词: 流速分布； 明渠； 湍流； 对数定律； 猝发现象 |
| DOI：10.13522/j.cnki.ggps.2017.0455 |
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| 基金项目: |
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| Velocity Distribution within Open Channel Studied Using the Average Structure of Turbulent Flow |
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LIU Xiaodong, HAN Yu, QIU Liuchao, YU Yang
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1.China Agricultural University, Beijing 100083, China; 2.Tsinghua University, Beijing 100084, China
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| Abstract: |
| 【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】①The 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%. ②Compared 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 2D 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. |
| Key words: velocity distribution; open channel; turbulence; log-law; bursting phenomenon |
