CES模型计算复式河槽过流能力及方法对比

Comparison between CES model and other models for calculating discharge capacity of compound river channel

复式河槽的洪水漫滩后,滩槽水流相互作用,在滩槽交界处形成动量交换,若直接采用曼宁公式进行水力计算将产生很大误差。应用CES(Conveyance Estimation System)模型首先计算了不同复式河槽的垂线平均流速,并结合英国科学工程研究理事会洪水水槽设备(SERC-FCF)的试验资料进行了验证,进而分析了不同形态复式河槽的水流特性;然后通过对比分析CES模型与经验方法(湿周修正法、断面分割法)和理论方法(谢汉祥法、刘沛清法、河槽协同度法)计算流量时的精度,论证了该模型在复式河槽水力计算中的优越性。结果表明,由CES模型计算的断面垂线平均流速分布符合复式河槽的水流特性且与实测资料吻合良好,较之其他模型方法,该模型能适用于任意形态复式河槽的流量计算且精度较高。

The interaction of flow occurs between the floodplain and the main river channel after the flood in the composite river channel overflows, which will form momentum exchange at the junction of the river channel and the floodplain. This will lead to great errors if the Manning formula is directly used for hydraulic calculation. The average vertical velocity of different composite river channels is calculated by the CES (Conveyance Estimation System) model and this model is verified by using the experimental data from British Science and Engineering Research Council flood channel facility (SERC-FCF), and then the analysis of the flow characteristics of different compound river channels is carried out in this study. Finally, by comparing and analyzing the accuracy of the CES model with that of empirical methods (such as wet perimeter correction method and cross-section segmentation method) and theoretical methods (such as the Xie Hanxiang method, Liu Peiqing method and coordination method) in calculating the discharge, the superiority of this model for hydraulic calculations of the compound river channels is demonstrated. The analysis results show that the distribution of the average vertical velocity given by the CES model method is in good agreement with the measured data, and it also accords with the flow characteristics of the compound river channels. Moreover, the CES model, compared with other models, is more suitable for the discharge calculation of the compound river channels with arbitrary shape and has higher accuracy.