梯形断面是渠道设计中广泛采用的一种断面形式,边界剪切应力分布规律是研究水流结构及阻力特性的重要因素。经过理论推导,建立了梯形明渠床面与边壁平均剪切应力相对值随过水断面宽深比的计算表达式,并与多家试验资料进行了比较,结果表明两者变化趋势基本一致。针对梯形明渠不同边坡角下的水力最优断面,分析了其床面、边壁平均剪切应力的变化规律,发现随着边坡角的减小,床面平均剪切应力相对值变化不大,而边壁平均剪切应力相对值呈现出减小的趋势。
Abstract
Trapezoidal section is widely used in the design of channels. The regularity of boundary shear stress distribution is an important factor in the research of flow structure and resistance.In this article, the expressions of the relative values of average bed and sidewall shear stress with width-depth ratio of flow section are derived through integration. Comparison between the present calculation method and Knight’s experimental data reveals relatively small error. The variation regularity of average bed and sidewall shear stresses of optimal hydraulic section in trapezoidal open channels with different side angels is analyzed. The result shows that the optimal hydraulic section in trapezoid open channel is narrow and deep, the average bed shear stress changes little while the average sidewall shear stress reduces with the decrease of side angel.
关键词
梯形明渠 /
床面平均剪切应力 /
边壁平均剪切应力 /
过水断面宽深比 /
水力最优断面
Key words
trapezoidal open channel /
average bed shear stress /
average sidewall shear stress /
width-depth ratio of flow section /
optimal hydraulic section
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参考文献
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