松花江洪水对嫩江顶托特性的数值模拟研究

摘要

为研究松花江洪水对嫩江的顶托规律,基于二维非结构化网格水动力模型MIKE21-FM进行了不同来流量级、不同汇流比条件下嫩江和二松交汇区水流运动数值模拟.突出分析了典型区域水位和水面比降的变化特性,探讨了嫩江受二松顶托的几个主要因素.结果表明,嫩江大赉站水位随嫩江来流量增加而增加,随汇流比增加而减小.嫩江水面比降随汇流比增加而增加.来流量、汇流比、河道坡降和距离等因素均会对顶托作用产生影响.今后应重点关注该区域洪季大流量且汇流比较小情况下的水情预报及防洪调度工作.%In order to study the backwater effects of Songhua River flood to Nen River,the river flow of Nen River and Er'song River confluence area is simulated on the condition of different discharge and discharge ratio based on a two-dimensional unstructured grid hydrodynamic mathematical model,MIKE21-FM.The characteristics of the changing of water level and water slope are analysed in the typical region.Several major factors of the backwater effects of Songhua River flood to Nen River are discussed.The results show that the water level of Dalai increases with the rising of Nen discharge and decreases with the rising of the discharge ratio.The water slope of Nen River increases with the rising of the discharge ratio.Some factors,such as river discharge,discharge ratio,channel gradient and distance,all will impact on the backwater effects.In the future we should focus on the hydrological forecasting and flood control work under the circumstance of large discharge and small discharge ratio in the flood season.