明渠水流阻力研究现状分析

Analysis of the present situation of open channels roughness

只有正确深入地把握水流阻力规律,才能掌握解决水力学及河流动力学中各种实际问题的主动性。本文通过系统评述和研究分析前人成果,对相关问题有所澄清。历史上曾经影响较大且不需要调整参数的杜博公式、艾特魏因公式、曼宁第二公式,可反映曼宁公式所代表的平均情况,但难以像曼宁公式那样能够适应自然界复杂多变的摩阻特性。至于巴辛公式,若将其河道粗糙特征的系数与曼宁糙率系数建立关系,同样能够适用于水流阻力计算。对于动床阻力问题,众多学者已认识到水流强度、河床形态的变化及流体中含沙浓度的重要影响,也通过不同角度建立了一些经验或半经验公式。为能找出实用性强或精度高的计算公式,还必须注重分析水流、河床与泥沙运动之间相互影响的内在机理,尤其需要在各种因子的影响机理及计算途径上开展深入研究。

This paper clarified the related problems on open channels roughness through the system review and analysis of the previous results.Du Buat formula,Eytelwein formula and Manning＇s second formula which do not need to adjust the parameters and have historical influence can reflect the average case,but hard to adapt to the nature of friction characteristics as Manning formula.Bazin formula is also applicable to flow resistance calculation after building the relationship between the Bazin roughness coefficient and Manning roughness coefficient.As for the problem of resistance in movable bed,many researchers have recognized the important influence of intensity of flow,change of the river morphology and sediment concentration and established some formulae.In order to establish practical and precision calculation formula,it must focus on the analysis of the intrinsic mechanism of interaction between flow,river bed and sediment movement,especially be needed in the in-depth study of the mechanism of a variety of factors and computational ways.