臺灣博碩士論文加值系統

許多海洋學者由現場內波觀測的結果證實，下沈型內波在傳遞過程中因地形淺化能轉變為上舉型內波。在大洋深海之處，上下層水深比適合下沈型內波存在，而當內波接近大陸邊緣時，上下層水深比通過轉折點(該處上下層水深相近)後，上層水深大於下層，不利下沈型內波之繼續存在，導致原有波形逐漸轉化為上舉型內波。
本研究於實驗室觀察下沉型孤立內波於類似大陸階之內波波形演化過程。實驗時使用一座12×0.7×0.5公尺的鋼架內波水槽，水槽內以淡鹽水密度差異造成分層水體，分別在長、中與短三種梯形底床障礙物，平台長度與高度分別為：(4.8x0.37m、1x0.35m及0.5x0.35m) 執行下沉型孤立內波之實驗。實驗時改變平台上兩層水體厚度(即H1>Ｈ2''、H1=Ｈ2''及H1<Ｈ2'' )及造波區位能差η0，重複造波，以模擬下沉型內波遭遇大陸階之變化。藉由綜理實驗結果，分析以上變因對波形演化及相關物理量的影響，可歸納內波重要波動特性：
當內波抵達梯形障礙物迎坡面時，引發多種波形演化現象，如溯下在梯形前斜坡發生渦旋、內水躍及溯上等。梯形障礙物平台上方兩層水體厚度比為決定下沉型孤立內波是否可能演化為上舉型內波之主要因素。依平台上方不同水深比對波形演化之影響可分為三種：(1) H1>Ｈ2'' 時，因平台段的上下水深比不利於下沉型內波的存在，致波型轉變為似上舉型內波；(2) H1=Ｈ2'' 時，內波傳遞於平台時，其波形以一水團狀態向前繼續傳遞，未有明顯之轉變；(3) H1<Ｈ2'' 時，內波傳遞在障礙物過程，保持上層水深小於下層水深，故仍以下沉型傳遞，無波型演化。
由試驗發現內波在不同平台長度上傳遞能影響內水躍作用範圍。平台長度越長平台上水體體積越大，其內水躍作用範圍越大，強度亦越大，短梯形障礙物之內水躍最小。重複多次造波後，內水躍受密躍層增厚的限制，導致水躍作用深度向上抬升，內波傳遞的振幅、波速亦逐漸隨之衰減。

Many oceanographers have postulated that internal wave form inversion would take place at the turning point where the thickness of the upper and bottom layer are equal in a stratified two-layer fluid system. This implies that an internal wave of depression may convert into elevation as the wave propagates over a continental margin comprising continental slope and shelf.
Laboratory experiments were conducted on the propagation of a depression ISW over a trapezoidal obstacle in a stratified two-layer fresh/brine water system in a steel framed wave tank of 12m long with cross section of 0.7m high by 0.5m wide. The relative difference in water depth between the upper and lower layer and the initial ISW amplitude were the main controlling parameters, among others. The water depth in the stratified two-layer system on the horizontal plateau of the trapezoid obstacle fell into one of the following case: (1) the upper layer larger than lower
(H1>Ｈ2''); or (2) equal depth in the upper and lower layer (H1=Ｈ2''); or (3) the upper layer less than lower layer (H1<Ｈ2''). In addition of the depth ratio, the difference in the length of the horizontal plateau and the thickness of the phycnocline above if were also parameters affecting the outcome of the experiments. In these experiments, three different type of the height and length of the trapezoidal obstacle were used, including long (4.8x0.37m), medium (1x0.35m) and short (0.5x0.35m) types. A full account on the characteristics of the ISW evolution observed during this experimental study is presented in this thesis. As an ISW propagated on the fronting slope, were run-down, vortex motion, internal hydraulic jump (IHJ) and run-up were occurred. Once the wave passed the turning point (where the depth of upper and lower layer equal), the wave form became elevation on the plateau above the obstacle.
Based on the laboratory data available, the effect on internal wave evolution can be evaluated by the relative fluid thickness (H1/Ｈ2'') on the plateau. The outcome can be classified into three categories: (1) H1>Ｈ2'', the relative layer thickness on the plateau unfits for depression ISW propagation and waveform behaves like elevation type; (2) H1=Ｈ2'', wave boluses containing mixed fluid propagating on the plateau after breaking on the slope; (3) H1<Ｈ2'', ISW propagated over trapezoidal obstacle subjected to shoaling and viscosity effect, without change in waveform.
As a depression ISW propagated over the variable length of the plateau, another important factor affecting the intensity of the internal hydraulic jump was the water volume drawn from the plateau. In the case of long horizontal plateau, the interaction range was large, and the IHJ was strong. Consequently, the thickness of the increased which caused the IHJ to move upward along the fronting slope. However, the amplitude and phase speed of the resulting internal wave decreased as if propagated further.

目錄
中文摘要 I
英文摘要 II
目錄 IV
符號表 VII
圖目錄 VIII
表目錄 X

第一章 緒論 1-1
1.1 前言 1-1
1.2 文獻回顧 1-2
1.2.1 現場研究調查 1-2
1.2.2 實驗室觀測 1-4
1.2.3 數值模擬內波研究 1-5
1.3 研究目的 1-6
1.4 本文架構 1-6
第二章 內波基本理論 2-1
2.1 前言 2-1
2.2 內波的生成、傳遞和衰減 2-2
2.2.1 內波的生成 2-3
2.2.2 內波的傳遞 2-5
2.2.3 內波的衰減 2-9
第三章 實驗室佈置 3-1
3.1 實驗設備與儀器 3-1
3.2 實驗步驟與流程 3-5
3.3 實驗項目 3-7
3.3.1 長梯型障礙物試驗 3-7
3.3.1.1 實驗項目與障礙物配置 3-7
3.3.1.2 實驗儀器之佈置 3-8
3.3.1.3 實驗項目統計 3-9
3.3.2 中梯型障礙物試驗 3-11
3.3.2.1 實驗項目與障礙物配置 3-11
3.3.2.2 實驗儀器之佈置 3-11
3.3.2.3 實驗項目統計 3-13
3.3.3 短梯型障礙物試驗 3-14
3.3.3.1 實驗項目與障礙物配置 3-14
3.3.3.2 實驗儀器之佈置 3-14
3.3.3.3 實驗項目統計 3-15
第四章 實驗數據整理 4-1
4.1 孤立內波在梯型障礙物的波形演化 4-1
4.1.1 長梯型障礙物上孤立內波實驗影像 4-1
4.1.2 短梯型障礙物上孤立內波實驗影像 4-7
4.2 孤立內波的物理參數 4-9
4.2.1 振幅(wave amplitude,ai、ai'' ) 4-9
4.2.2 孤立內波波速(phase speed,Ci) 4-9
4.2.3 浮動頻率(buoyancy frequency, N) 4-9
4.2.4 特徵波長(characteristic wave length, L) 4-9
4.2.5 內波能量(wave energy, E) 4-10
4.2.6 內水躍下拉最低深度(Hd) 4-10
4.2.7 破碎臨界水深(Hu) 4-11
4.3 實驗數據結果 4-12
4.4 實驗室內波理論驗證 4-22
4.4.1 實驗室內波與理論波形的比較 4-22
4.4.2 實驗水體密度與理論密度剖面比較 4-25
第五章 實驗結果分析與比較 5-1
5.1 實驗室孤立內波波形轉換比較 5-1
5.1.1 孤立內波振幅的變化 5-2
5.1.2 孤立內波振幅轉換率 5-4
5.1.3 孤立內波波速變化 5-7
5.1.4 孤立內波波長變化 5-8
5.1.5 孤立內波局部波長變化 5-12
5.1.6 孤立內波淨能量變化 5-13
5.2 內波於梯形障礙物前斜坡的內水躍分析 5-14
5.2.1 梯型障礙物前斜坡的內水躍現象 5-15
5.2.2 內波受內水躍影響的變化 5-17
5.2.3 不同障礙物平台長度對內水躍的影響 5-20
5.2.4 梯型障礙物密躍層之變化 5-23
5.2.5 內水躍受密躍層厚度影響之振幅變化率 5-25
5.3 孤立內波於短梯型障礙物之變化 5-28
5.3.1 長、短梯型障礙物上之內波振幅衰減 5-28
5.3.2 短梯型障礙物對下沉型孤立內波傳遞之影響 5-29
第六章 結論與建議 6-1
6.1 結論 6-1
6.2 建議 6-2
參考文獻 參-1

參考文獻
Apel, J.R., J.R. Holbrook, J. Tsai, and A.K. Liu, (1985). The Sulu Sea internal
soliton experiment. J. Phys. Oceanography, 15(12): 1625-1651.
Ariyaratnam, J., (1998). Investigation of slope stability under internal wave action. B.Eng. (Hons) thesis, University of Western Australia, Australia.
Bogucki, D., and C. Garrett, (1993). A simple model for the shear-induced decay of
an internal solitary wave. J. Phys. Oceanography, 23: 1767-1776.
Bole, J.B., J.J. Ebbesmeyer, and R.D. Romea, (1994). Soliton currents in South China Sea: measurements and theoretical modelling. Proc. 26th Annual Offshore Tech. Conf., Houston, Texas, pp. 367-375.
Chen, Y.C., J.C.R. Hsu, C.F. Kuo, H.H. Chen, and M.H. Cheng (2006). Laboratory
Observations on Internal Solitary Wave Evolution over a Submarine Ridge.
China Ocean Engineering, 20(1): 61-72.
Chen, Y.C., J.C.R. Hsu, C.W. Chen, H.H. Chen, C.F. Kuo, and M.H. Cheng
(2007a). Generation of internal solitary wave by gravity collapse. Journal of
Marine Science and Technology, 15(1): 1-7.
Chen, Y.C., J.C.R. Hsu, C.W. Chen, H.H. Chen, C.F. Kuo, and M.H. Cheng
(2007b). Wave propagation at the interface of a two-layer fluid system in the
laboratory. Journal of Marine Science and Technology, 15(1): 8-16.
Chen, Y.C., J.C.R. Hsu, H.H. Chen, C.F. Kuo, and M.H. Cheng (2007c). Laboratory observations on internal solitary wave evolution on steep and inverse uniformslopes. Ocean Engineering, 157-170.
Chen, Y.C., J.C.R. Hsu, M.H. Cheng, H.H. Chen, and C.F. Kuo (2007d). An
investigation on internal solitary waves in a two-layer fluid: Propagation and
reflection from steep slopes. Ocean Engineering, 171-184.
Ebbesmeyer, C.C., and R.D. Romea, (1992). Final design parameters for solitons at selected locations in South China Sea. Final and Supplementary reports prepared for Amoco Production Company. 209pp. plus appendices.
Ekman, V.M., (1904). On dead-water. Sci. Results, Norwegian North Polar Expedition,5(15): 1893-1896.
Garrett, C.J.R., and W.H. Munk, (1992). Space-time scales of internal waves. Geophys. Fluid Dyn., 3: 225-264.
Haury, L. R., M.G. Briscoe, and M. T. Orr, (1979). Tidally generated internal wave
packets in Massachusetts Bay. Nature, 278-312.
Helfrich, K.R., and W.K. Melville, (1986). On long nonlinear internal waves over
slope-shelf topography. J. Fluid Mech., 167: 285-308.
Honji, H., N., Matsunaga, Y. Sugihara, and K. Sakai, (1995). Experimental observation of interanl symmetric solitary waves in a two-layer fluid. Fluid Dyn. Res., 15 (2): 89-102.
Hsu, M.K., and A K. Liu, (2000). Nonlinear internal waves in the South China Sea. Canadian Journal of Remote Sensing, 26: 72-81.
Huttemann, H., and K. Hutter, (2001). Baroclinic solitary water waves in a two-layer fluid system with diffusive interface. Experiments in Fluids, 30 (3): 317-326.
Jacobs, W., (1997). The effect of density stratification on surface and internal gravity waves, B.Eng (Hons) thesis, Univ. Western Australia, Australia.
Kao, T.W., and H.P. Pao, (1979). Wake collapse in the thermocline and internal solitary waves. J. Fluid Mech., 97: 115-127.
Knickerbocker and Newell, (1980). Internal solitary wave near a turning point. Physical Letters 75A(5) 326-330.
Koop, C.G., and G. Butler, (1981). An investigation of internal solitary waves in a two-fluid system. J. Fluid Mech., 112: 225-251.
LeBlond, P.H., and L.A. Mysak, (1978). Waves in the Ocean. Amsterdam: Elsevier.
T.W. Lin, (2001). A study on internal waves characteristics in north of South China Sea,” Master Thesis, Institute of Oceanography, National Taiwan Univ., Taiwan. (In Chinese).
Liu, A. K., S. R. Ramp, Y. Zhao, and T. Y. Tang, (2004). A case study of internal solitary wave propagation during ASIAEX-2001. IEEE J. Oceanic Eng., 29: 1144-1156.
Lynett, P. J., and L -F. Liu, (2002). A two-dimensional, depth-integrated model for internal wave propagation over variable bathymetry. Wave Motion, 36: 221–240.
1144-1156.
Maxworthy, T., (1979). A note on the internal solitary waves produced by tidal flow
over a three-dimensional ridge. J. Geophys. Res., 84, 338-346.
Moore S.E., and R.C. Lien, (2007). Pilot whales follow internal solitary waves in the South China Sea. Marine Mammal Science, 23(1): 193-196.
Nagashima, H., (1971). Reflection and breaking of internal waves on a sloping beach. J. Oceanographical Soc. Japan, 27(1): 1-6.
Orr, M.H., and P.C. Migneret, (2003). Nonlinear internal waves in the South China Sea: Observation of the conversion of depression internal waves to elevation internal waves. J.G.R., 108(C3):3064.
Osborne, A.R., Burch, T.L. and T.I. Scarlet, (1978). The influence of internal waves
on deepwater drilling . J. Petroleum Tech., 30: 1497-1504.
Osborne, A.R., and T.L. Burch, (1980). Internal solitons in the Andaman Sea. Science, 208 (4443): 451-460.
Perry, R.B., and G.R. Schimke, (1965). Large-amplitude internal waves observed off
the northwest coast of Sumatra. J. Physical Oceanography, 70(10): 2319-2324.
Ramp, S.R., T.Y. Tang, T.F. Duda, J.F. Lynch, A.K. Liu, C.S. Chiu, F.L. Bahr, H.R. Kim, and Y.J. Yang, (2004). Internal solitons in the northeastern south China Sea. Part 1: sources and deep water propagation. IEEE Journal of Oceanic Engineering, 29(4): 1157-1181.
Sandstrom, H., and J.A. Elliott, (1984). Internal tide and solitons on the Scotianshelf: a nutrient pump at work. J. Geophys. Res., 89(4): 6415–6426.
Sveen, J.K., Y. Guo, P.A. Davies, and J. Grue, (2002). On the breaking of internal solitary waves at a ridge. J. Fluid Mech., 469 (25): 161-188.
Sveen, J.K., and S.B. Dalziel, (2007). A dynamic masking technique for combined measurements of PIV and synthetic schlieren applied to internal gravity waves. Meas. Sci. Technol. 16 (2005) 1954–1960.
Thrope, S.A., (1975). The excitation, dissipation, and interaction of internal waves in
the deep ocean. J. Geophysical Research, 80(3): 328-338.
Vlasenko, V., and K. Hutter, (2002). Numerical experiments on the breaking of solitary internal waves over a slope-shelf topography. J. Phys. Oceanography, 32(6): 1779-1793.
Vlasenko, V., L. Ostrovsky, and K. Hutter, (2005). Adiabatic behavior of strong nonlinear internal solitary waves in slope-shelf areas. J.G.R., 110(C4):C04006.
Wang,Y.H., C.F. Dai, and Y.Y. Chen, (2007). The physical and ecological processes of internal waveson an isolated reef ecosystem in the South China Sea. Geophysical Research Letter, 34, L18609,doi:10.1029/2007GL030658.
West, B.J., (1981). Nonlinear properties of internal waves. Proceedings of American
Institute of Physics, New York, 76: 353-359.
Zheng, Q., R. D. Susanto, C.-R. Ho, Y. T. Song, and Q. Xu, 2007. Statistical and
dynamical analyses of generation mechanisms of solitary internal waves in the
northern South China Sea, J. Geophys Res., 112, C03021, doi:10.1029/2006
JC003551, (SCI), (NSC 95-2611-M- 019-008-MY3).