一維數值模式對隘口土砂調節功能之評估

The Evaluation of River Notch Sediment Regulating Capacity by 1D Numerical Model

林家興(Chia-Hsing Lin) ； 林士勛(Shih-Hsun Lin) ； 劉政儒(Cheng-Ju Liu) ； 謝正倫(Chjeng-Lun Shieh)

《中華防災學刊》 9卷1期 (2017/02) Pp. 31-40

摘要

本文以數值模式對河道天然隘口土砂調節功能評估進行改善。藉以瞭解河道隘口在上游大規模土砂流出事件發生時之土砂調節能力評估。為改善河道地形寬度突縮模擬準確度，修正動量方程並導入河道寬度突縮時所產生的水壓力變化項。再進行數值實驗測試模式穩定性及守恆性以探討模式之穩定性及準確度。最後再以渠道實驗作為數值模式之驗證，探討定床水流縱剖面變化及動床土砂堆積縱剖面變化。最後數值模擬以隘口之束縮比、囚砂率及排砂折減率進行分析，其結果顯示出本數值模式對河道隘口寬度突縮地形影響下之水理變化及土砂堆積特性，可提供良好之模擬結果。

關鍵字

隘口 ； 土砂調節功能 ； 一維水理模式

並列摘要

The study applied one dimensional numerical model to evaluate the variation of hydraulic and sediment regulating capacity when large scale sediment event occurred. In order to improve the accuracy of numerical model for simulation sediment regulating capacity in river notch, the numerical model modified the pressure force term of momentum equation respond to the river width variation. The numerical model was tested the stability, water and sediment volume conservation analysis to demonstrate the stability and precision of numerical model. Laboratory investigation was carried out to validate the hydraulics and sediment deposition variation. The simulation results were comparable to laboratory experiments. The numerical simulation considered contraction ratio, contraction length, contraction inlet angle, and upstream sediment supply rate to understand sediment regulating capacity. The result of numerical tests showed that numerical model has the ability to simulate the hydraulics and sediment deposition dynamic response of river width variation affected by river notch.

並列關鍵字

River Notch ； Sediment Regulating Capacity ； One-dimension Hydrodynamic Model