Vertical distribution of streamwise velocity and its prediction in Ushaped channel
YANG Shi-Hong1, HAN Jin-Xu2, PENG Shi-Zhang1, GAO Xiao-Li1, GU Hong3, LI Jiang-An3
(1. State Key Laboratory of HydrologyWater Resources and Hydraulic Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 2. Yellow River Institute of Hydraulic Research, Zhengzhou, Henan 450003, China; 3. Gaoyou Municipal Water Affairs Bureau, Gaoyou, Jiangsu 225600, China)
Abstract To find a guide to water management in field irrigation, the vertical distribution of streamwise velocity in a Ushaped open channel was clarified by means of indoor and field experiments. In addition, a twopower law for such a distribution was established by using the law of velocity in asymmetric closed channel. The methods for defining the parameters in the twopower law were given, and then the law was validated by the experimental data. The results showed that the flow velocity was lowered with increasing water depth, but the peak velocity appeared under the free surface. The predicted velocity distribution by the twopower law agreed with the experimental data in the 0.10-0.95 dimensionless depth so well that the error was as small as 5%, suggesting the law can involve the effect of free surface and channel wall. Compared with the traditional law of velocity distribution, the twopower law is more accurate, and may be used in an open channel with a crosssection of other shape.
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