漫滩水流动量修正系数特性分析与模拟

摘要

Based on the shallow water hydrodynamic model of Shiono & Knight for compound channel flows,the characteristics of floodplain flow were analyzed.The study shows that the momentum correction coefficient increases rapidly when floodplain flow happens,and decreases subsequently.The degree of the coefficient' s variation will be larger under larger width ratio between floodplain and channel.But the momentum correction coefficient calculated by the conventional cross-section averaged method is equal to one constantly,which does not agree with the real discipline.To solve this problem,a new method calculating the momentum correction coefficient is proposed.In the end, experimental datum is used to verify the method.%以明渠深度平均二维水流模型为基础,研究了漫滩水流的动量修正系数.结果表明,漫滩瞬时动量修正系数迅速增大,随后快速减小;滩槽宽度比越大,动量修正系数变化程度越大,而传统断面平均法的计算结果恒为1,与实际情况存在较大差异,不能用于水流漫滩的模拟.为了反映动量修正系数的实际变化规律,提出了水流漫滩时断面动量修正系数新的计算方法,最后采用模型试验和天然河道实测资料对该方法进行了检验.