Application of Hydrodynamic Model to Investigate the Characteristics of Hydraulic Gate Exit – An Example of Jinliujie Embankment,Yilan

本研究旨在應用二維水理模式CCHE2D分析不同角度之排水渠道，對內水渠道排洪流量之影響。以宜蘭縣金六結堤防做為研究樣區，金六結堤防平日為無水狀態，但逢豪大雨、颱風等期間，附近區域雨水皆往此處排入，然金六結堤防堤外河床地勢較低，內水的排放較為緩慢，大水退後堤內農田仍處於泡水狀態導致農作物損失。爰此，本研究嘗試透過改變排水渠道角度，選定90°、60°及30°做為試驗方案，透過模擬放流期間流場變化情形，瞭解試驗渠道渦流發展過程及水流移動路徑，再者，分析各方案比流量模擬結果，判斷排水角度的改變對出口段流量變化之影響，據以做為優勢方案挑選依據。 經三種不同方案流場模擬結果可知，隨排水渠道出流角度減少，來流流場分離點後仍形成迴流區，然迴流區長度由90°方案延伸至出流口邊界降至1倍水門寬；而在流速方面，90°方案排水渠道出口流速僅0.6 m/s，當出流角度達30°時，流速大幅提升至 1 m/s以上。而就比流量分析成果而言，90°方案受排水渠道左側迴流區之影響較為劇烈，比流量由側向溢流開口 0.210 m2/s 逐漸向下游衰退，最終排水渠道出口之最大比流量僅約 0.10 m2/s，然隨排水渠道角度減少，側向溢流開口比流量向下游衰退幅度銳減，30°方案之排水渠道出口之最大比流量仍達 0.17 m2/s 以上。根據本研究模擬分析成果顯示，縮小內水渠道與排水渠道之夾角，可大幅提升排水渠道之排洪量，減少退水後內水無法順利洩洪之問題。This study aims to analyze the drainage channels of different angles by using the two-dimensional hydraulic model CCHE2D. The Jinliujie Embankment in Yilan County was selected as a research area. Jinliujie embankment is usually waterless. During heavy rain or typhoon, rainwater from nearby areas is discharged here. But the bottom of the Jinjiliujie embankment is lower than outside, internal water emissions are slower. This study attempts to change the angle of the drainage channel. Selected 90°, 60° and 30° as case to simulate the flow-field change with CCHE2D. The result can understand the eddy current development process and the flow path of water flow. And analyzing the simulation results of specific discharge, determining the influence of the angle-change drainage. The flow field simulation results of three different caes show that outflow angle reduced with drainage channel. The recirculation zone is still formed after the separation point of the flow field However, the length of the recirculation zone extends from the 90° case to the outlet boundary and is reduced to 1 times the width of the gate. In terms of velocity, the 90° case outlet is only 0.6 m/s. When the outflow angle reaches 30°, the flow rate is greatly increased to above 1 m/s. And compared to the results of specific discharge. The 90° case is more affected by the left recirculation zone of the drainage channel. The specific discharge is gradually degraded downstream by the lateral overflow opening 0.210 m2/s. Finally, the maximum specific discharge of drainage channel outlet is only about 0.10 m2/s. But as the angle of the drainage channel decreases, the lateral overflow opening decreases sharply than the flow rate decreases. The maximum specific discharge of the 30° case outlet still reaches 0.17 m2/s or higher. According to the results of this study, reducing the angle between the inner channel and the drainage channel can significantly increase the drainage volume of drainage channels. Reducing the problem that the inner water can not be discharged smoothly after the water was decreased.摘要 i Abstract ii 目錄 iv 圖目錄 vi 表目錄 ix 第一章 緒論 1 1-1. 研究緣起 1 1-2. 研究目的 3 1-3. 本文架構 3 第二章 文獻回顧 4 2-1. 閘門分類 4 2-2. 自動閘門改良研究 20 2-3. 水理數值模式維度選擇 26 2-4. 二維水理模式 28 2-5. 小結 46 第三章 研究樣區與方法 47 3-1. 研究樣區介紹 47 3-2. CCHE-2D模式理論 50 3-3. CCHE-2D設定及所需參數資料說明 54 3-4. CCHE-2D模式代表案例 65 第四章 結果與討論 69 4-1. 分析方案 69 4-2. 分析條件 69 4-3. 流場分析結果 72 4-4. 比流量分析結果 92 第五章 結論與建議 114 5-1. 結論 114 5-2. 建議 115 參考文獻 11