优选法求解天然河道水面曲线方程

Application of Optimum Seeking Method in Solving Curve Equation for Natural River Water Surface

为推求闸坝等壅水建筑物的回水影响，或计算河道工程（如筑堤、改河等）修建前后河道水流状态的改变，常需推算河道水面线。这类问题大多属于不恒定流，应使用圣维南方程求解。但在天然河道水面线计算中，为了节省工作量把不恒定流视为恒定流。当出现不满足简化特定条件时，常出现“死循环”现象。本文采用优选法解决了“死循环”的不收敛问题。

In order to calculate the backWater effect caused by a gate or a dam to the backWater structure,or to evaluate the change of river water flowing state before/after construction of river water projects such as building an embankment or modifying a river course,the curve for discribing river water surface is commenly to be deduced.Due to the instability of flow of the river water,such a problem is often discribed by a solution of Sanvinan equation.However,the unstable flow is usually considered as stable flow in the calculation of natural river water surface curve in order to minimize the calculation work.In case that thd specific conditions for simplifying the calculation cannot meet the requirement,the “dead cycle” phenomena appears.In this paper,the eptimum seeking method is adopted to solve the problem of non convergence of the dead cycle.