Abstract
It is now over half a century since Keulegan conducted his open channel flow experiments. Over the past decades, many empirical formulae were proposed based on his results, however, there is still not a combined expression to describe the effects of friction over all hydraulic regions in open channel flows. Therefore, in this letter, based on the analysis of the implicit model and the logarithmic matching method, the results of Keulegan (for authentic experiment data are no longer available, here we adopt the analytical solutions given by Dou) are rescaled into one monotone curve by combining the Reynolds number and the relative roughness of the river bed. A united expression that could cover the entire turbulence regions and be validated with Dou’s analytical solutions is suggested to estimate the friction factor throughout the turbulent region in open channel flows, with higher accuracy than that of the previous formulas.
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Project supported by the National Natural Science Foundation of China (Grant Nos. 51479007, 11172218 and 11372232), the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20130141110016).
Biography: LI Shuo-lin (1994-), Male, Ph. D. Candidate
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Li, Sl., Shi, Hr., Xue, Wy. et al. United friction resistance in open channel flows. J Hydrodyn 27, 469–472 (2015). https://doi.org/10.1016/S1001-6058(15)60506-6
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DOI: https://doi.org/10.1016/S1001-6058(15)60506-6