本研究應用一維性非恆態流水理模式模擬雨水下水道分流之明渠流水理現象,本研究之一維性非恆態流水理模式應用普里斯曼隱性差分技巧(Preissmann''s Scheme)及數值法模擬使用聖凡南假設(Saint Venant Hypotheses)推導連續方程式及動量方程式,並以數值雙掃法求解。上游之邊界條件為設計入流歷線,下游之邊界條件為非恆態水位歷線,並假設一恆態流之基底流量,由基底流量及下水道系統上、下游之邊界條件使用標準步推法(Standard-Step Method)求得各管渠之初始水深。 本模式主要模擬馬蹄形管渠之明渠流水理現象,並以水工模型試驗之結果分析各人孔之水深與管渠之流量,驗證模式各項參數之準確性。 This research applys Preissmann''s scheme and Double-Sweep Methos to establish a model to solve Continuity Equation,which is according to Saint Venant Hypotheses.The upstream boundary condition is assumed to be designed discharging hydrograph,while the downstream boundary condition is suumed to be water stage hydrograph of tidal.The base which discharges at each channel is assumed with a small discharge.Assumed the fact that the flow is steady.The initial depth of this model involves in downstream boundary condition''s effect and is derived from downstream end using Standard-Step Method. This model is mainly simulates the horsehoe-shaped tube to open channel flow and base on the experiment result to prove the validity and accuracy of each parameter can be tested.