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| DOI：10.13522/j.cnki.ggps.2017.0455 |
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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 |
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