表面波與內波是在許多大洋中普遍存在的一種自然現象。目前大部份海洋學者認為內波對表面波影響遠大於後者影響前者，即內波傳遞時在表層發生短暫流，進而影響表面波。在大洋中當內波傳遞至海底山脊附近，因內波破碎引發大幅度渦動，此作用對表面波傳遞勢必造成相對變化。近年來，雖有多位學者在國際期刊提出這種現象的相關理論推導，但至今鮮少有表面波與內波相互影響的研究與實驗，以供驗證。
本研究於國立中山大學內波實驗室內進行實驗，探討表面波與內波傳遞通過單一山形障礙物時波動特性之演化。實驗時使用一座12 × 0.5× 0.7公尺的鋼架內波水槽，在其內部佈置兩層水體（上層密度為996kg/m3；下層密度1030kg/m3），以點撞式造波機（plunging type）造波，依所需實驗項目產生上層所需之表面波動，並間接於界面層衍生內波群。
此外藉由不同水深比探討當表面波與內波群通過單一山形障礙物時，障礙物上方與障礙物後方之兩者波動特性的變化。藉由整理實驗結果，分析以上變因對表面波及內波波動特性之轉變及相關物理量的影響。在等密度的均質水體中，進行表面波通過山形障礙物實驗時，發現當總水位較淺時，障礙物上方之表面波因碎波，波浪振幅減小，而在通過山形障礙物後方時，表面波有再生現象，其波高相較於障礙物上方為大，且主要週期亦恢復原始週期。而在雙層水體中之表面波與內波通過山形障礙物實驗中發現，若內波因距離障礙物較遠，波浪與障礙物的輕度作用，使振幅與週期幾乎不變，但在障礙物上方的表面波則有週期變長，但振幅幾乎無改變的結果；而在碎波作用時可知，當表面波與內波傳遞至山形障礙物時對，波浪頻譜的變化較為顯著，內波本身振幅減小，週期稍減，而表面波則受因內波碎波的影響，其振幅增大但週期則減小。
由分析多組不同水深比與造波條件的數字，可以統計方法找出適當的實驗經驗式，再與既有的學理公式相驗證，提供現場觀測之依據或數值模式的邊界關係。

Surface gravity waves and internal waves are two of the most common natural phenomena in the ocean. While oceanographers believe that internal waves have greater influence over the surface waves, if is not clear to what extent that the former have affected the latter. As an internal wave propagating in the ocean, short period flow could be induced on the free surface layer. Moreover, as internal waves propagating over a submarine ridge, internal breaking accompanying by large vortex may have occurred, which may also affect the properties of the surface waves. To prove the relationship between them, basic mathematical equations have been derived, but had never been proven in the laboratory experiments or field observations.
In this thesis, the results of a series of laboratory experiments conducted at the National Sun Yen-sen University are employed to study the waveform evolution and change to the physical parameters of the surface waves, resulting from the generation of internal waves induced on a stratified fluid, as both propagate together above a plane bottom or across single ridge. These experiments were carried out in a stratified two-layer fresh/brine water system (upper layer with fresh water density 996 kg / m3; bottom layer brine water with 1030 kg / m3) in a steel framed wave tank of 12m long with cross-section of 0.7 m high by 0.5 m wide. A plunging-type wave maker was used to produce the designated surface waves, from which the internal waves were induced at the interface.
Based on the experimental results in the fluid system with uniform density, wave height and period of the surface wave were first calibrated. It was found that the amplitude of a surface wave decreased first due to the breaking of the internal wave on the apex of a submerged ridge and then increased due to wave regeneration at the back of the ridge, when the surface wave propagated over single ridge. Beyond the ridge, the peak period with maximum energy associated with the transmitted wave remained almost the same with that of the incident waves. In a stratified fluid system, wave height of the surface waves and internal waves did not suffer much change but the peak period of a surface wave increased as an internal wave just across the apex of the obstacle, under a condition referred to as weaken interaction between the waves and the obstacle. For the intense wave breaking condition at the interface, wave height of the internal waves decreased and the period of surface waves or internal waves shortened. However, wave height of the surface wave above the apex of the obstacle increased due to the intense wave breaking.
The results obtained from the present laboratory experiments on the interaction between a surface wave and the induced internal wave could benefit others interested in surface and internal wave interaction for practical applications in oceanography or numerical modeling.

謝誌 I
摘要 II
Abstract III
目錄 V
符號說明 VII
圖目錄 VIII
表目錄 XI
第一章 緒論 1
1.1 前言 1
1.2 文獻回顧 2
1.2.1 現場研究調查 2
1.2.2 實驗室研究 6
1.3 研究目的 7
1.4 本文架構 9
第二章 內波基本理論與分析方法 11
2.1 內波生成機制 11
2.2 內波消散機制 12
2.3 傳統不規則波浪之頻譜分析 13
2.4 FFT (Fast Fourier transform) 頻譜分析 14
2.5 HHT(Hilbert-Huang Transform)時間-頻率分析的理論架構 16
2.6 EMD（Empirical Mode Decomposition Method）經驗模態分解法 17
2.6.1 篩選過程（Siffing Process） 17
2.6.2 整合經驗模態分解法（Ensemble EEMD） 21
第三章 實驗室佈置 25
3.1 實驗設置 25
3.2 研究步驟 29
3.3 實驗量測儀器之佈置 32
3.4 實驗條件 34
3.5 實驗項目 35
第四章 實驗數據初步彙整 39
4.1 實驗室實驗情況說明 39
4.1.1 輕度作用 39
4.1.2 碎波作用 40
4.2 造波機之波動率定 45
4.3 實驗室實驗條件參數 47
4.4 實驗室數據結果 49
第五章 實驗數據分析與討論 59
5.1 均質水體實驗 59
5.1.1 表面波波形 59
5.1.2 均質水體中表面波造波的參數率定 60
5.2 雙層水體無障礙物實驗 63
5.2.1 雙層水體無障礙物實驗的波形圖 63
5.2.2 表面波波動特性在雙層水體與均質水體無障礙物實驗之差異 66
5.3 均質水體有障礙物實驗 68
5.4 雙層水體有障礙物實驗 76
5.4.1 雙層水體有障礙物實驗之波形與頻譜分析 76
5.4.2 均質水體及雙層水體有障礙物實驗之波動特性與無因次參數關係 92
第六章 結論與建議 94
6.1 結論 94
6.2 建議 95
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