明渠水流边壁影响修正的计算方法

Sidewall correction method of open-channel flows

针对窄深明渠及岸壁附近的明渠水流泥沙运动进行研究时,常常需要除掉岸壁的作用以便了解床面剪切应力的影响。以往对边壁影响修正的方法是基于一些没有完全被验证的假设,床面剪切力的计算数值可能受所采取的边壁修正的方法影响。本研究在分析可靠资料的基础上,发现爱因斯坦对数阻力公式不但可以用于计算不同断面形式的平均的水流情况,而且可以分别用于边壁和床面的阻力计算。将分别对应于边壁和床面的爱因斯坦阻力公式应用阻力计算中,可以解决方程组不闭合的问题。试验资料分析表明,本文提出的方法有较高的精度。

When investigating sediment transport or other hydraulic phenomenon in narrow open-channel flows,it is often necessary to remove sidewall effects for computing the effective bed shear stress.Previous sidewall correction methods are subject to some assumptions that have not been completely verified and different values of the bed shear stress may be obtained depending on the approach used in making sidewall correction.Based on the analysis of reliable data,it is found that the Einstein logarithmic resistance formula can be used to calculate not only the mean flow of a section,but also the resistance of sidewall and bed,respectively.When the Einstein logarithmic resistance formula is used to calculate the resistance of sidewall and bed flow respectively,the closure problem of equation group can be solved.This study also demonstrates by experimental results that this correction method has high precision.