應用影像分析於潰壩後下游動床與水面變動之研究

Abstract

本文主要以試驗的方式來觀測潰壩流流經下游之運動形態，文中包含定床試驗及動床試驗。而根據前人之研究，研究維度可分為一維試驗及二維試驗，但在量測動床變化仍侷限於一維試驗。前人的研究鮮少探討底床與時間歷程之變化關係，故本試驗進行潰壩流之二維動床試驗，並進一步探討動床床型隨時間變化的關係。 本文利用雷射切頁以及數位影像分析量測潰壩流流經下游隨時間之變化關係。於定床案例中，上游初始水深分別為5公分、10公分及15公分。而在動床部份則分別設定上游水深為5公分、10公分及5公分，上游動床分別設定為5公分、10公分及10公分，下游動床則設定為5公分、10公分及7.5公分。而雷射切頁以及數位影像分析量測則是從壩下游側往下游距離45公分內之範圍，則量測所有試驗條件下，水位隨時間變化與動床高度隨時間之變化。本研究同時納入數值模式，分析其於定床試驗之適用性，並提供試驗資料作為後續模式發展之用。

The study observes dam break flow through downstream movement patterns by experiment methods. This paper contains the fixed bed model and moving bed model tests. Base on previous research, the research of various dimension model could be classified into one-dimensional model and two-dimensional model, but the measurement of the movable bed change is still restricted to one-dimensional experiment. Previous studies rarely investigated the relationship between the seabed changes and time ; therefore, this study conducted in the dam break flow test in two-dimensional movable bed and further explore the relationships of movable bed type and time. The laser sheet and digital images analysis will be used in analyzing measurements the change over time of the dam break flows through downstream. In fixed bed model experiments, the depth of initial upstream water includes 5 cm, 10 cm and 15 cm. And in the moving bed model, the depth of initial upstream water includes 5 cm, 10 cm and 5 cm, upstream bed were set at 5 cm, 10 cm and 10 cm, and downstream bed is setting to 5 cm, 10 cm and 7.5 cm. The laser sheet and digital image analysis measurement range is 45 cm from the rear gate, we would exactly measure the water level changes over time and bed height change over time in all test conditions. The study also includes numerical model to analyze the suitability of fixed bed and moving bed trial model and provide experiment data for further innovational development.