一維河岸及河床變動水理模式之研究

每當洪水事件發生時，所帶來的大量雨水不僅會對河床之地形產生變化，更會對河岸進行侵蝕，進而危及河道兩岸居民的安全。因此河道治理時需要一套有效模擬河川地形變動之模式，本研究目的在建立一維河道土砂運動模式可模擬出河道沿程之水理、底床高程與河寬變動之現象。模式的主要架構串接水理計算模組、輸砂計算模組、底床高程變動模組及河岸變動模組，其中運用Parker等人（2007）所推導河寬變動方程式作為河岸變動模組之主要核心理論。模式採用之數值方法是以顯式有限差分法（Explicit Finite Difference Method）再配合計算流體力學方法中的Laxwendroff法，將模式採用之基本方程式離散化處理，並運用分離演算法（Uncoupled Method）以計算水、砂之運動過程。最後以Cantelli（2004）實驗作為模式驗證的案例，對於模擬移除壩後的底床高程與橫斷面水面寬之變動情形，模式計算成果與實驗結果有相同之趨勢，顯示出本模式在模擬河床與河岸變動上具有相當的準確性。

關鍵字

一維輸砂模式；河道動床；底床高程變動；河岸變動

並列摘要

When flood occur, it's often causing riverbank erosion and endangering inhabitants near the river bank. Therefore, the purpose of this research is established a one-dimensional movable bed numerical model; it can simulate the river bed and bank evolution. The model combine hydrodynamics, sediment transportation, river bed evolution and river bank evolution. For the river bank evolution, Parker's (Cantelli, 2007) derivation is applied. The model applied two-step Lax-Wendroff's explicit finite difference scheme which possesses second-order accuracy and higher stability. Artificial viscosity is provided into the equation of momentum to dampen the numerical oscillation caused by hydraulic jump or drop down. In order to test the result of numerical simulation is reasonable and reliable; the research simulated the Cantelli's experiment (Cantelli, 2004) as verification. In the simulation case under the influence of removal of dam is used to simulate elevation of river bed and width of channel.

並列關鍵字

one-dimensional sediment transportation model ； movable bed ； bed evolution ； bank evolution

國際替代計量

一維河岸及河床變動水理模式之研究

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