下边界条件为水位流量关系的扩散波洪水演算方法研究

Study on Diffusive Wave Flood Routing for the Stage- Discharge Relationship Downstream Boundary Condition

经大量的理论分析和实际洪水演算表明 ,扩散波可较好地反映洪水波的运动特点。本文基于河道下断面的水位流量关系和连续方程的联立求解 ,导出了水位流量关系型的下边界条件。利用Laplace变换 ,得到了扩散波方程在该边界条件下的解析解。文中的求解过程表明 ,可利用该法进行洪水演算 ,关键在于如何与实际洪水结合 ,这个问题有待进一步地分析研究。

It is proved that the diffusive equation is accurate enough, but relatively simple, to calculate flood propagation both in theoretical and practical perspectives. The stage-discharge curve at the downstream boundary is combined with the continuity equation of the St. Venant equations to create the stage-discharge relationship type boundary condition for the downstream condition. The Laplace transform method is employed to obtain the analytical solution to the diffusive equation with the boundary condition. A case study indicates that the proposed method is adequate to calculate channel flood propagation.