非恒定水流的一维、二维耦合数值模型

从数值波在每一时间步长内传播的距离不超过Courant数个网格点的基础出发，采用时间滞后条件，构造了虚拟的重叠计算水域。利用重叠－投影法，在连接（点）处建立一、二维耦合模型，实现了由一维计算水域向二维计算水域的准确过渡。采用一、二维耦合模型和全一维模型对上海市淀南片河网的验证计算表明，一、二维耦合模型能较好地模拟非恒定水流，且具有一定的可靠性和实用性。

1-D and 2-D coupling numerical model of unsteady flow

Based on the fact that the information propagation distance in one time step can not be greater than the length of N (Courant number) grids, a new approach, namely overlapping projecting method, is proposed using the time delayed boundary condition. According to the method, a coupling model is developed to join the calculation domains of 1 D and 2 D numerical models. Comparison of the calculation results of the coupling model with those of 1 D model shows that the coupling model can simulate unsteady flow with tributaries and is stable, reliable and practical.