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对数型流速分布公式是描述河渠垂向流速分布的常用方法,但是公式中卡门常数K、积分常数B和尾流强度系数Π的取值一直没有确定。本文研究了对数型流速分布公式中上述3个参数的取值范围及其变化对流速计算结果的影响,以及摩阻流速u_*不同计算方法的精度和优缺点。对比分析了877个测点的流速计算值和实测值,结果表明:在浅宽和窄深渠道中,K取0.395,B取5.419时,不含尾流修正函数的对数型流速分布公式在计算流速分布上仍然具有较高的精度,可满足实际工程的需要。
Logarithmic flow velocity distribution is a commonly used method to describe the vertical velocity distribution of a river channel. However, the values of Carmen constant K, integral constant B and wake strength coefficient Π have not been determined. In this paper, we study the influence of the range of the above three parameters on the logarithm-type flow velocity distribution formula and its variation on the flow velocity calculation results, as well as the precision, advantages and disadvantages of the different calculation methods of the friction velocity u_ *. The calculated and measured values of 877 measuring points are compared and analyzed. The results show that the logarithm-type flow velocity distribution without wake correcting function is 0.395 for K and 5.419 for B, Calculating the flow velocity distribution still has a higher accuracy, to meet the needs of the actual project.