近幾十年來，隨著現場觀測儀器精進及在世界多處海域的探勘，海洋學家逐漸能瞭解內波的特性，尤其是內波生成、傳遞與消散等物理現象及促成在海洋物理及海洋生態領域的持續研究進展。雖然表面重力波與內波是海洋中的兩大波動但其相互作用仍未被完全瞭解，雖更多位學者於國際期刊提出相關理論推導，但至今少更利用水槽實驗，以探討表面波與內波的相互關係，提供學理驗證。
本研究於國立中山大學海洋科學院的內波實驗室進行實驗，討論連續內波群在水平底床及梯形障礙物上的波形演化。由在上層水體表面製造表面波而間接於界面層衍生內波群的方式，再安排數種上下層水深比、週期及造波機沒入表層深度，進行一系列實驗。由實驗結果可供探討在雙層水體於不同週期表面波波高的條件下能影響界面之最大深度，再由分析不同表面波波高及週期所衍生之內波波高，建立兩者波高關係圖。本研究進一步分析表面波於單、雙層水體傳遞至梯形障礙物時之波形變化；由結果發現(1)長週期表面波於雙層水體傳遞中較易受到內波影響，導致其波高更隨後減小之趨勢，(2)短週期表面波的波動反而無明顯的相互影響，故表面波波高與在單層水體中傳遞結果相似。
此外，本研究亦探討一連續型內波於大陸邊緣的傳遞及其波型轉換。由分析詴驗結果得知連續型內波週期的長短，對波型翻轉過程前在斜坡上所衍生的內水躍與局部渦漩強度更明顯的影響；週期短，則內波影響平台上方水體的水平距離亦隨之縮短，且內波與障礙物作用時間也減短。

Equipped with advanced field instruments in the past few decades, oceanographers have been able to comprehend some characteristics of the internal waves(IWs), such as the generation, propagation and energy dissipation, as well as to promote understanding in oceanography and marine ecology affected by IWs in the world ocean. Although surface gravity wave and internal wave are two of the most common natural phenomena in the ocean, the interaction between them has not been fully investigated, despite limited theoretical derivations in the literature, nor using laboratory experiments to verify the theory.
A series of laboratory experiments were conducted at the National Sun Yen-sen University to study the waveform evolution of continuous IWs propagation on the flat bottom and across a trapezoidal obstacle. Surface waves were generated on a density stratified fluid system in a wave flume, from which IWs were induced indirectly to investigate their wave properties associated with their propagation . The experimental results are then used to determine the maximum depth which could be affected by surface waves in different wave conditions(wave height and period), as well as the amplitude of the IWs induced. The relationship between them are then presented in graphic form. Experiments were also conducted in uniform density and stratified fluid system with a trapezoidal obstacle. The results reveal that (1)long-period surface waves were susceptible to the interaction with the IWs in a stratified system, thus rendering wave height reduction, and (2)short-period surface waves interactions with their IWs counterparts was insignificant, hence yielded wave height similar to that in uniform density fluid system.
Moreover, experiments were also conducted to study for long and short period IW propagated over pseudo slope-shelf(using trapezoidal obstacle). The results show that the variation in the IWs significantly affected the strength of internal hydraulic jump and vortices on the front slope and subsequent waveform inversion on the horizontal plateau. For IWs with short period, the horizontal distance on the plateau affected by the IWs was shirter and the total time of wave-topography interaction decreased.

謝誌................................................................................................................................. i
中文摘要...................................................................................................................... iii
Abstract .......................................................................................................................... v
目錄.............................................................................................................................. vii
圖目錄........................................................................................................................... xi
表目錄......................................................................................................................... xiv
符號說明...................................................................................................................... xv
第一章 緒論.................................................................................................................. 1
1.1 前言 .................................................................................................................. 1
1.2 文獻回顧 .......................................................................................................... 2
1.2.1 現場內波觀測研究 .................................................................................. 2
1.2.2 實驗室內波研究 ...................................................................................... 6
1.2.2.1 內波群(internal waves)實驗研究 ..................................................... 6
1.2.2.2 大陸階邊緣(slop-shelf)實驗研究 .................................................... 8
1.3 研究目的 .......................................................................................................... 9
1.4 本文架構 ....................................................................................................... 10
第二章 基本理論介紹................................................................................................ 11
2.1 內波的生成機制 ............................................................................................ 11
2.2 內波的傳遞機制 ............................................................................................ 12
2.3 內波的消散機制 ............................................................................................ 14
2.4 傳統波浪頻譜分析 ........................................................................................ 15
2.5 傅立葉轉換 .................................................................................................... 17
2.6 小波轉換 ....................................................................................................... 20
2.7 HHT 時頻分析 ............................................................................................... 20
2.7.1 瞬時頻率(Instantaneous Frequency) ..................................................... 21
2.7.2 希爾伯特黃轉換理論 ............................................................................ 22
2.7.2.1 經驗模態分解法(Empirical Mode Decomposition) ....................... 23
2.7.2.2 希爾伯特轉換(Hilbert Transform)及頻譜圖 ................................. 27
第三章 實驗配置........................................................................................................ 31
3.1 實驗方法 ........................................................................................................ 31
3.2 實驗步驟 ........................................................................................................ 33
3.3 實驗條件 ........................................................................................................ 35
3.3.1 水槽實驗條件 ....................................................................................... 35
3.3.2 數值模擬條件 ....................................................................................... 35
第四章 實驗結果概述................................................................................................ 37
4.1 水槽實驗條件參數 ........................................................................................ 37
4.2 主要週期的定義 ............................................................................................ 39
4.2.1 長週期(T=18 s) ...................................................................................... 40
4.2.2 強複合性週期(T1=4.4 s，T2=8.9 s) ..................................................... 41
4.2.3 弱複合性週期(T1=3.6 s，T2=6.0 s) ..................................................... 42
4.2.4 短週期(T=4.6 s) .................................................................................... 43
4.2.5 極短週期(T=3.2 s) ................................................................................ 44
4.3 HHT 分析說明 ............................................................................................... 45
4.4 波動傳遞影片分析 ....................................................................................... 48
4.4.1 長週期型連續內波傳遞過程(T=18 s) ................................................. 48
4.4.2 極短週期型連續內波傳遞過程(T=4 s) ................................................ 50
4.4.3 複合性週期連續內波傳遞過程(T1=3 s，T2=6 s) ................................ 52
第五章 數據分析與討論............................................................................................ 55
5.1 表面波於分層水體傳遞特性 ....................................................................... 55
5.1.1 表面波的影響水深 ............................................................................... 55
5.1.1.1 波形初步分析................................................................................. 55
5.1.1.2 波高-週期-最小影響水深比 .......................................................... 57
5.1.2 表面波傳遞 ........................................................................................... 66
5.2 連續內波於梯形障礙物傳遞之特性差異 ................................................... 68
5.2.1 長週期內波群(T=18 s) ......................................................................... 68
5.2.2 強複合性週期內波群(T1=8.8 s，T2=4.4 s) ......................................... 72
5.2.3 弱複合性週期內波群(T1=3 s，T2=6 s) ............................................... 76
5.2.4 短週期內波群(T=5 s) ........................................................................... 80
5.2.5 極短週期內波群(T=4 s) ....................................................................... 83
5.2.6 傳遞過程中內波特性變化 ................................................................... 87
5.2.7 能量變化率 ............................................................................................ 89
第六章 結論與建議.................................................................................................... 91
參考文獻...................................................................................................................... 95
附錄1 單層水體於水平底床實驗條件................................................................... 101
附錄2 雙層水體實驗條件....................................................................................... 102

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