臺灣博碩士論文加值系統

摘要

本研究以水工模型試驗的方式，探討規則波通過斜坡上橢圓淺灘地形時，其波場因地形變化因素而引起之變形。試驗中，探討波浪以不同角度、週期入射，且著重於大角度斜向入射後探討其波場中折、繞射現象與橢圓淺灘後方能量集中、聚焦現象，進而了解橢圓淺灘周圍波場波浪變形之情況。
試驗結果發現淺灘上方波高增大，且因產生折、繞射變化，淺灘後方有能量集中、聚焦之情形，而長週期時能量聚焦現象較短週期時明顯，聚焦區域也因不同入射角度而變化，角度較大時折射現象顯著，導致聚焦區域變形彎曲。
橢圓淺灘周圍的波場中，其前方因反射使波高略增，而折、繞射現象則使兩側波高略減，後方部份區域劇增及部分區域驟減即能量集中、聚焦所致。能量集中、聚焦於近岸區域，不利於海岸之保護，因此試驗結果將作為後續考量能量消散於近岸區域之試驗比較參考用。

Abstract

An experiment in hydraulic model test, this research investigate the deformation of wave field caused by the variations in terrain when regular wave passes through the elliptic shoal. In these experiments, we aim to discuss the phenomenon of refraction, diffraction , energy concentration and focus in wave field behind the elliptic shoal while the waves in different incident angles and periods. Therefore, the further understanding of the waves’ deformation in wave field near the elliptic shoal can be achieved. Based on experiments, it is found that the wave in upper part of the shoal enlarged, and both the energy concentration and focus were found in the back of the shoal because of the refraction and diffraction. Furthermore, it indicated that the phenomenon of focus from long period wave was more significant than the one from short period wave, and focus was varied according to the differences in incident angles. Meanwhile, the refraction was tended to be obvious when the angle was wide. This also led to the focus deformed and curved.
Within the wave field of the elliptic shoal, the wave height in the front increased a little bit due to the reflection. On the other hand, the wave height near the two sides decreased a little bit because of both the refraction and diffraction. In addition, part areas in the back either increased sharply or decreased instantly were all caused by the energy concentration and the focus.To sum up, the energy concentration and the focus in the nearshore zone will be harmful to the protection of coasts. Therefore, this study applied here will be viewed as a beneficial reference to the follow-up consideration for an experiment of energy disappeared in the nearshore zone.

中文摘要 I
Abstract II
目 錄 III
照片、表目錄 VI
圖目錄 VII
第一章 緒論 1
1-1研究動機與目的 1
1-2前人研究 2
1-3研究方法 3
1-4本文組織 4
第二章 試驗配置與方法 5
2-1試驗設備和儀器 5
2-1-1平面水槽 5
2-1-2蛇形造波機 5
2-1-3波高計和增幅器 6
2-1-4資料擷取系統與軟體 8
2-2試驗模型製作與配置 8
2-2-1試驗地形的鋪設與佈置 8
2-2-2試驗儀器設置與量測範圍 12
2-3試驗前置作業 17
2-3-1波高計率定 17
2-3-2造波條件率定 18
2-4試驗條件 18
2-5資料分析方法 19
2-6試驗流程 20
第三章 試驗結果與分析 21
3-1平面波場變化 21
3-1-1規則波正向入射 21
3-1-2斜向入射（θ=15°） 24
3-1-3斜向入射（θ=30°） 27
3-1-4正向及斜向入射之結果比較 29
3-2縱向及橫向之波高變化 30
3-2-1規則波正向入射 30
3-2-2斜向入射（θ=15°） 35
3-2-3斜向入射（θ=30°） 40
3-3橢圓淺灘上方波高變化分析 45
3-3-1正向入射 45
3-3-2斜向入射（θ=15°） 48
3-3-3斜向入射（θ=30°） 50
3-4橢圓淺灘後方波高變化分析 52
3-5橢圓淺灘前方波高變化分析 57
第四章 結論與建議 60
4-1結論 60
4-2建議 61
參考文獻 62
謝 誌 64
作者簡歷 65

參考文獻

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