复式河槽流量计算方法比较与分析

复式河槽在洪水漫滩后，直接运用曼宁方程计算过流能力将带来很大误差。本文系统地总结了复式河槽流量计算的各种方法，运用这些方法分别计算整个复式断面的流量和滩槽流量分配，并与英国科学工程研究协会洪水水槽设施 (SERC-FCF)的大量的系列水槽实验成果进行比较。通过比较发现：计算流量时，断面垂直分割法、单一河槽法和等速剖分法误差都很大；而其它方法精度都比较高。运用流量计算精度比较高的方法同时计算流量分配发现：对某一具体断面形态而言，很难准确说哪种方法的精度最高。通过对各种方法的综合分析，建议在计算天然复式河槽过流能力时，采用河槽协同度方法。

Comparison of methods for calculating flow capacity of channels with compound cross section

Considerable error may occur to the calculation of flow capacity for channels with compound cross section by means of Manning formula, when flood is out-of-bank and flooding of plain is happened. In this paper, various methods are used to calculate the discharge of the whole cross section and the discharge allocation between main channel and flood plain. All calculation results are compared with the experimental data from Science and Engineering Research Council Flood Channel Facility (SEREFCF). It is found that the precisions of Cross-Sectional Vertical Division Method, Single Channel Method and Equivalent Velocity Division Method are poor. Based on the comprehensive analysis for available methods, the authors suggest that it is preferably to use the Channel Coherence Method to calculate the flow capacity and analyze the discharge allocation of channels with compound cross section.