洪涝仿真模型中河网洪水的计算研究

为在洪涝仿真模型中计算河网及工程调度下的洪水演进,并综合考虑河道洪水与地面洪水的相互影响,本文建立了一维圣维南方程和河网汊点水量平衡方程组,按照preissmann四点差分格式进行离散,采用泰勒级数近似的方法计算了河网中跨河闸门在关闭、自由出流和淹没出流三种状态下的过流能力,利用并修改了矩阵标识法求解方程组,研发了一维河网模拟模型;利用堰流公式建立一维河网模拟模型和二维洪涝仿真模型的连接,实现了一、二维模型的耦合。从文献中选择典型算例验证模型,模拟结果与文献相同。以长江、汉江和东荆河河网及杜家台和洪湖蓄洪区为工程实例,模拟的河网洪水与实测数据基本一致,河道与两个蓄洪区的水量交换合理,证明新建立的一维河网模拟模型具备了对河网洪水演进的模拟能力,与二维模型耦合的方法合理。

Calculation on flood of river network in flood simulation model

In order to simulate flood routing in river network with the regulation of water conservancy projects in flood simulation model，whilst considering the interaction between rivers and overland flood，the one-dimensional ( 1D) saint-venant equations and junction mass-conservation formulas are established to develop 1D dynamic model for river network. To compute flow through water conservancy projects such as weir or sluice，Taylor Series approximation method is used，and three status including sluice closure， free flow or submerged flow of the projects are simulated. The equations are discretized by using four-point difference schemes，and solved by adopting and improving the matrixlabel method. The new established 1D river network model is coupled to two-dimensional ( 2D) flood simulation model by adopting weir formulas. Typical cases in literatures are adopted to validate the model，and the simulated results are same to the literatures. Ｒiver network comprising Yangtze Ｒiver，Han Ｒiver and Dongjing Ｒiver，and two flood detention areas named Dujiatai and Honghu are taken as pilot area，simulated flood is similar to observed data and flow exchange between rivers and the two detention areas is reasonable. The new established 1D model and coupling method with 2D model are proven to be feasible and scientific.