卡艾瑋臺灣大學:土木工程學研究所侯鈞耀Hou, Chun-YaoChun-YaoHou2010-06-302018-07-092010-06-302018-07-092009U0001-1108200916233200http://ntur.lib.ntu.edu.tw//handle/246246/187749本文利用實驗和數學來測試湖和支流對河川形貌動力的影響。在實驗方面，我們利用小型的水箱來模擬河川渠道以及改變實驗的初始條件來測試不同的河川形貌。在數學上，為了能夠描述實驗室裡的河川形貌，我們利用Saint Venant方程式和Exner方程式並以適當的小尺寸的條件簡化成小尺寸的河川模式。此外，對於不同的河川形貌，我們推導出不同的解析解。之後，我們將實驗、小尺寸的河川模式及解析解作比較，證實小尺寸的河川模式及解析解是否可以描述實驗室裡小尺寸的河川形貌。最後，我們應用這樣方法到現地實際的情況，來證明現地不同的河川形貌也可以用簡單的方式來描述。In this thesis, experiments and mathematics are used to probe the effect of lake storage and tributaries influx on river morphodynamics. For the experiments, we use a small-scale lab tank (100~200cm length and 1cm width) to model river channel change under different test conditions. To describe the fluvial morphology in the laboratory, we then deduce a microscale fluvial model from the Saint Venant equations and Exner equations. In addition, we also find analytical solutions for different special cases. We then compare the microscale numerical model and analytical solutions with the lab data to check whether they can effectively describe the evolution of the fluvial morphology. We apply this approach to a variety of river-lake configurations observed in the field, such as barrier lake, dam breaching, and tributary-dammed lake, etc. It is formed that simple rules can lead to a variety of fluvial morphologies.誌謝………………………………………………………………………………………I要……………………………………………...…………………………………….IIbstract…………………………..………..….…...……………………………………IIIontents…………………………….....…….……………………………………...…. IVigure lists…………………………………...…...………………………………….…VIable lists………………………...…………..…………………………………….…XIIIhapter 0 Introduction………………………………..………………………………....1hapter 1 General Theory…………………………..…………………………………...5-1 Governing Equation in General…………..………………………………………..5-2 Simplified for Micro Scale………….……………………………………………...6-2.1 Simplifying Saint Venant Equations…………………………………………..7-2.2 Simplifying Exner Equation………………………………………………….10-3 Computational Scheme…………………………………………………………...11-3.1 Computing Flow Depth………………………………………………………12-3.2 Computing Bed Elevation……………………………………………………13-3.3 Some Numerical Problems...…………………………………………………15-4 Analytical Similarity Solution……………………………………………………16hapter 2 Microscale Barrier Lake……………..……………………………………..21-1 Conditions of Occurrence………………………………..……………………….22-2 Experiment………..………………………………………………………………21-2.1 Set-up…………………………………………...……………………………22-2.2 Parameters……………………………………..……………………………..25-2.3 Process and Analysis…...…………………………………………………….28-3 Analytical Solutions…………………...………………………………………….33-3.1 The Downstream of Barrier Lake…………………………………………..34-3.2 The Upstream of Barrier Lake………………………………………………36-4 Comparison……………………………………………………………………….42-4.1 Calibrating Parameters……………………………………………………….42-4.2 Results………………………………………………………………………..43-5 Discussion…………………………………………………...……………………46hapter 3 Microscale Knickpoint……………..……………………………………….49-1 Conditions of Occurrence…………………………………..…….………………49-2 Experiment………………………………………………………………………..50-2.1 Set-up, Parameters and Process…………..…………………………….……50-2.2 Analysis and Results…………………………………………………………54-3 Analytical Solution……………………….………………………………………55-3.1 Unchanged Mobile Bed……………………………………………………...56-3.2 Horizontal Half-Infinite Mobile Bed……………...…………………………57-3.3 Result……………………………………………………………………...…60-4 Comparison……………………………………………………………………….61-5 Discussion………………………………………………………………………...64hapter 4 Microscale Dam Breaching………….……………………………………..67-1 Conditions of occurrence……………………………………………………….67-2 Experiment………………………………………………………………………..68-2.1 Set-up…………..…………………………………………………………….68-2.2 Parameters and Experimental Processes……………………………………..70-2.3 Analysis………………………………………………………………………72-3 Analytical Solution…………………………….…………………………………80-3.1 The Rectangular Dam………………………………………………………..81-3.2 The Triangular Dam……………………………………………………….…83-3.3 The Change of Outflow Discharge…………………………………………..86-3.4 Solving and Computing Scheme……….…………………………………….88-4 Comparison Analytical Solution and Experiments……..……...…………………91-5 Discussion……………………………………………………………………...…96hapter 5 Microscale Tributary-Trunk River Junction…..………………………….101-1 Conditions of Occurrence………………………………….……………………101-2 Experiment………………………………………………………………………102-2.1 The First Phase: Only Tributary…………………………………………….102-2.2 The Second Phase: Main River and Tributary…….………………………..109-3 Analytical Solutions...……………………………….…………………………..123-3.1 Tributary-Induced Cuspate Aggradation……………………………………123-3.2 The Tributary-Dammed Lake……………………………………………….126-3.3 Lake-Truncated Fan…………………...……………………………………129-3.4 Symmetrical Tributary Fan…………………………………………………136-3.5 The Limits of Categories of The Fluvial Morphology……………………...138-4 Comparison……………………………………………………………………...140-5 Discussion……………………………………………………………………….152hapter 6 Conclusions………………………………………………………………..157eferences……………………………………………………………………………..1638132458 bytesapplication/pdfen-US湖支流潰壩河川形貌微小尺寸laketributarydam breachingfluvial morphologymicroscalethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/187749/1/ntu-98-R96521312-1.pdf