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J4  2009, Vol. 43 Issue (6): 1102-1106    DOI: 10.3785/j.issn.1008-973X.2009.06.023
    
Laws of velocity distribution in trapezoidal open channels
HU Yun-jin1, GAO Hui-cai2, GENG Luo-sang3,CAI Fu-kuan4
(1.Department of Hydraulic and Ocean Engineering, Zhejiang University, Hangzhou 310027, China;
2. Zhejiang Institute of Hydraulic and Estuary, Hangzhou 310002, China;
3. Management Center of Hydraulic Information of Zhejiang Province, Hangzhou 310002, China;
4.Third Harbor Engineering Investigation and Design Institute, China Transportation Engineering, Shanghai 200032,China)
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Abstract  

In order to study the velocity distribution in trapezoidal open channels, a 3-D turbulent numerical model, which had been verified by measured results, was used to numerically simulate the flow in 12 different kinds of trapezoidal open channels combined by different base slopes, different wall roughnesses and different aspect ratios. Results showed that the vertical distribution of flow velocity in the bottom inner region of open channel conforms to logarithmic distribution, but that in the outer region conforms to power function distribution, while the transverse distribution of equivalent mean velocity in vertical conforms to power function distribution. Through the least square fitting, laws of vertical distribution of velocity and transverse distribution of equivalent mean velocity in vertical were obtained. The velocity values calculated by the laws of velocity distribution agreed well with the measured values. Therefore, the laws of velocity distribution presented herein provide herein are reasonable and can be applied to the accurate measurement of flux of trapezoidal open channels.



Published: 01 June 2009
CLC:  TV133  
Cite this article:

HU Yun-Jin, GAO Hui-Cai, GENG Luo-Sang, et al. Laws of velocity distribution in trapezoidal open channels. J4, 2009, 43(6): 1102-1106.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2009.06.023     OR     http://www.zjujournals.com/eng/Y2009/V43/I6/1102


梯形断面明渠流速分布的研究

为研究梯形断面明渠的流速分布律,应用经过实测资料验证的三维紊流数学模型,对12种不同底坡、不同糙率以及不同宽深比组合情况下的梯形断面明渠水流流速分布进行了数值仿真.结果表明,在明渠底部内区流速分布能很好地符合对数分布,但在明渠外区流速分布更符合乘幂函数分布,等效线平均流速沿横向的分布接近于乘幂函数分布.通过最小二乘拟合,得到了梯形断面明渠垂线流速分布律和等效线平均流速横向分布律.按流速分布律计算的流速值与实测值吻合较好,表明所给出的断面流速分布律是合理可靠的,可应用于梯形断面明渠流量的精确测量.

[1] STEARNS F P. A reason why the maximum velocity of water flow in open channels is below the surface[J]. Transactions ASCE, 1883, 7(4): 331338.
[2] VANONI V A. Velocity distribution in open channels[J]. Civil Engineering, 1941, 11(6): 356367.
[3] COLES D. Law of the wake in the turbulent boundary layer[J]. Journal of Fluid Mechanics, 1956, 1(2): 191226.
[4] 胡春宏,倪晋仁. 矩形明槽中断面紊流流速分布规律的初步研究[J]. 水利水运科学研究, 1988(2): 2735.
HU Chun-hong, NI Jian-ren. Study on the law of turbulent velocity profile in rectangular open channels[J]. Hydro-Science and Engineering, 1988(2): 2735.
[5] 孙东坡,王二平,董志慧,等. 矩形断面明渠流速分布的研究及应用[J]. 水动力学研究与进展, 2004, 19(2): 144151.
SUN Dong-po, WANG Er-ping, DON Zhi-hui,  et al. Discussion and application of velocity profile in rectangular open channel[J]. Journal of Hydrodynamics, 2004,19(2):144151.
[6] YANG S Q. Interaction of boundary shear stress, secondary currents and velocity [J]. Fluid Dynamics Research, 2005, 36(3): 121136.
[7] 张长高. 梯形断面明槽中恒定均匀流的流速分布[J]. 河海大学学报, 1998, 26(5): 1721.
ZHANG Chang-gao. Velocity distribution of steady flow in trapezoidal open channels[J]. Journal of Hohai University, 1998, 26(5): 1721.
[8] 张兰丁. 用流场分析法计算明渠流量[J]. 水利水运科学研究, 1996(3): 277282.
ZHANG Lang-ding. Computing discharge in open channel by analytic method of flow field [J]. Hydro-Science and Engineering, 1996(3): 277282.
[9] 陈永灿, 朱德军. 梯形断面明渠中纵向离散系数研究[J]. 水科学进展, 2005, 16(4): 511517.
CHEN Yong-can, ZHU De-jun. Study on longitudinal dispersion coefficient in trapezoidal open channel [J]. Advances in Water Science, 2005, 16(4): 511517.
[10]蔡甫款. 明渠流量测量的关键技术研究[D]. 杭州: 浙江大学, 2006.
CAI Fu-kuan. Study on some key techniques of open channel flow measurement[D]. Hangzhou: Zhejiang University, 2006.

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