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博碩士論文 etd-0905108-100229 詳細資訊
Title page for etd-0905108-100229
論文名稱
Title
錨碇雙浮筒運動特性研究
Study on the dynamics of a moored floating dual pontoon
系所名稱
Department
畢業學年期
Year, semester
語文別
Language
學位類別
Degree
頁數
Number of pages
96
研究生
Author
指導教授
Advisor
召集委員
Convenor
口試委員
Advisory Committee
口試日期
Date of Exam
2008-06-25
繳交日期
Date of Submission
2008-09-05
關鍵字
Keywords
邊界元素法、數值水槽、雙浮筒
Dual pontoon, NWT, Boundary element method
統計
Statistics
本論文已被瀏覽 5662 次,被下載 1325
The thesis/dissertation has been browsed 5662 times, has been downloaded 1325 times.
中文摘要
本文旨在探討在二維波浪場中,波浪通過錨碇雙浮筒平台(moored floating dual pontoon platform) 時所產生的散射問題與輻射問題。以勢流理論(potential flow theory)為基礎,發展二維非線性數值水槽(2D nonlinear numerical wave tank ),模擬雙浮筒在波浪場中的動力特性,並以水工實驗的方式,在玻璃水槽(寬1m × 高1.2m × 長35m )內架設一錨碇雙浮筒平台,觀察波浪通過浮筒後的反射(reflection)與透過率(transmission),以及結構物的位移(translation)、旋轉運動(rotation)和纜繩的張力(tension),以驗證本文數值模式的可用性。
實驗結果發現,雙浮筒水平運動振幅(surge-RAO)隨著頻率增加而遞減,在低頻區surge-RAO上升的原因主要來自波浪頻率接近錨碇系統頻率而產生的共振。在垂直振幅(heave-RAO)方面,一開始隨著頻率增加而下降,但到某一頻率後則垂直振幅開始上升到一峰值後逐漸下降,這是由於入射波頻率在趨近heave共振頻率時會與結構物產生共振使物體垂直振幅增加,而當遠離共振頻率時,共振效應變小導致垂直振幅下降。張力振幅(tension-RAO) 有兩個共振頻率,低頻區的共振主要來自surge運動影響,而在較高頻區共振則是來自heave運動的影響。反射率與透射率在接近共振頻率時皆變小,顯示共振時大部份的波浪能量轉移到結構物上,而造成交互作用後波浪總能的變小,表示結構物在共振頻率區對入射波有很好的遮蔽效應。
數值結果與實驗比較顯示,除了在共振頻率附近,heave方向的數值結果較實驗值大之外,其他皆與實驗結果有很好的一致性,這是由於雙浮筒的邊緣為直角,共振時垂直流速增加,容易在底部發生分離流現象,此時黏性影響大而不可忽略,因此減緩了浮筒垂直方向的共振振幅。
Abstract
This paper is to study the scattering problem and radiation problem between incident wave and a moored dual pontoon platform by using both a fully nonlinear numerical wave tank (NWT) and a physical tank. The nonlinear numerical wave tank is developed based on the velocity potential function and the boundary element method (BEM). In addition, a moored dual floating pontoon physical model is tested in an experimental wave tank to validate the numerical model for simulation of wave and structure interaction including mooring tension, structure translation and rotation. The phenomena of wave reflection and transmission due to a floating platform are also considered in the study.
The experimential results indicate that the platform surge-RAO decays as the wave frequency increases. Similarly, the platform heave-RAO decays first until at the vicinity of the resonance frequency happening where the vertical amplitude rises up and then decays again. The tension-RAO has two resonance frequencies, the lower resonance is resulted by the surge montion, while the higer resonance is caused by the heave motion. Both wave reflection and transmission coefficients decrease near the heave resonance frequency. This indicates that the platform has the best performance in wave shelter effect at heave resonance to protect costal zone.
In general, the comparisons of the numerical simulations and experimental results indicate the numerical horizontal motion have a good agreement, but for the vertical motion, the numerical predictions are larger than experiments especially near the heave resonance frequency. This may be due to the structure vertical velocity increases dramatically causing flow separation occurred below the structure sharp corner, thus the fluid viscous damping effect may play an important role in heave motion.
目次 Table of Contents
中文摘要……………………………………………………………………………………….i
英文摘要……………………………………………………………………….......………… ii
目錄………………………………………………………………………….………………..iii
圖目錄…………………………………………………….…………………………………..vi
表目錄………………………………………………….……………………………………...x
第一章 緒論…………………………………………………………………………………..1
1.1 前言……………………………………………….…………………………………..2
1.2 文獻回顧……………………………………………………………………………...2
1.3 研究目的…………………………………………………………………………...…3
1.4 研究方法……………………………………………………………………………...3
1.5 文章架構………………………………………………………………………….......4
第二章 理論基礎……………………………………………………………………………..5
2.1 二維數值水槽理論…………………………………………………………………...5
2.1.1控制方程式……………………………………………………………………...5
2.1.2邊界積分方程式………………………………………………………………...5
2.1.3 邊界值問題 ……………………………………………………………………6
2.2 結構物外力計算……………………………………………………………………...9
2.3 加速勢………………………………………………………………………………...9
2.4 隱式邊界條件法…………………………………………………………………….11
第三章 數值方法……………………………………………………………..……….……13
3.1 邊界積分離散化…………………………………………………………………….13
3.2 Time Marchin Scheme……………………………………………….………………14
3.2.1 Mixed Eulerian-Lagrangian method………………………..………………..15
3.2.2 曲線座標統……………………………………………….…………………...15
3.2.3 固體與液體交界面處理………………………………………………………15
3.2.4 RK4…………………………………………………….…...………….…….15
3.3 數值消波區………………………………………………………………………….16
3.4 緩衝方程式………………………………………………………………………….18
3.5 節點重置…………………………………………………………………………….18
3.6 平滑化………………………………………………..……………...………………18
第四章 水工模型試驗………………………………………………………………………19
4.1 實驗目的…………………………………………………………………………….19
4.2 實驗規劃…………………………………………………………………………….19
4.2.1 相似理論及模型縮尺………………………………………………………19
4.2.2 平台系統……………………………………………………………………..21
4.2.3 實驗儀器與設備……………………………………………………………..22
4.2.4 實驗佈置……………………………………………………………………..26
4.2.5 實驗步驟……………………………………………………………………..26
4.2.6 實驗波浪設計條件…………………………………………………………..29
4.3分析分法……………………………………………………………………………..29
4.3.1 能量分析……………………………………………………………..………30
4.3.2 張力分析………………………………………………………….………… 30
4.3.3 平台剛體運動析…………….……………………………………………… 30
第五章 結果與討論…………………………………………………………..…………….32
5.1 入射波高的影響……………………………..…………………………………….. 34
5.2 纜繩夾角的影響…………………………..………...……..………………………..38
5.3網帶的影響…………………………………………………………………………..41
5.4 水深的影響………………………………………….………………………………44
5.5 彈性係數的影響…………………………………………………..…………….......48
5.6 浮筒間距的影響…………………………………………………..………………...51
5.7 不規則波的影響………………….………...……………………..………………...55
第六章 結論與建議...............................................................................................................60
參考文獻..................................................................................................................................63
附錄A 結構物運動邊界….................................................................................................... 65
附錄B 影像處理.....................................................................................................................70
附錄C 慣性矩.........................................................................................................................79
附錄D 反射率計算….............................................................................................................81
參考文獻 References
1. 王佩文(1997) 「繫纜式浮體結構在波浪作用下之動力行為分析」,國立中山大學海洋環境及工程系研究所碩士論文。
2. 黃添成(2002) 「水下雷射掃瞄量測系統CCD攝影機之校正」,國立中山大學海洋環境及工程系研究所碩士論文。
3. Black, J.L. and Mei, C.C., 1969. Scattering of surface waves by rectangular obstacles in water of finite depth. J. Fluid Mechanics, Vol. 38, pp. 499-511.
4. Black, J.L., Mei, C.C. and Bray, M.C.G., 1971. Radiation and scattering of water waves by rigid bodies. J. Fluid Mechanics, Vol. 46, pp. 151-164.
5. Brebbia, C. A., and Dominguez, J., 1989. Boundary Elements: An IntroductoryCourse, McGraw - Hill, New York, 45-91, 267-268.
6. Cointe, R., Geyer, P., King, B., Molin, B., Tramoni, M., 1991. Nonlinear and linearmotions of a rectangular barge in perfect fluid. Proc. of the 18th Symp. on Naval Hydro., 85-98.
7. Grilli, S.T. and Svendsen, I.A. 1990. Corner problems and global accuracy in the boundary element solution of nonlinear wave flows. Engineering Analysis.
8. Goda, Y., Suzuki, Y., 1976. Estimation of incident and reflected waves in random wave experiments. Proceedings of the 15th International Conference Coastal Engineering, pp. 628-650.
9. Goda, Y., 1999. A comparative review on the functional forms of directional wave spectrum. Coastal Engineering Journal 41(1), 1-20.
10. Hsu, T.W., Hsiao, S.C., Ou, S.H., Wang, S.K., Yang, B.D., Chou, S.E., 2007. An application of Boussinesq equations to Bragg reflection of irregular waves. Ocean Engineering 34, 870-883.
11. Kim, C. H., Clément, A.H., Tanizawa, K., 1999. Recent research and develop- pment of numerical wave tanks - A review. Int. J. Offshore and Polar Eng. 9(4), 241-256.
12. Koo, W. C., Kim, M. H., 2004. Freely floating-body simulation by a 2D fully nonlinear numerical wave tank. Ocean Engineering 31, 2011-2046.
13. Lee, C.-P. and Lee, J.-F., 1993. Wave induced surge motion of a tension leg structure Ocean Engineering, Vol. 20, No.20,pp.171~186.withBoundary Elements, 7(4), 178-195.
14. Longuet-Higgins, M.S., Cokelet, E., 1976. The deformation of steep surface waves on water I. A numerical method of computation. Proc. Royal Society, London, Series A350, 1-26.
15. Ohyama, T., Nadaoka, K., 1991. Development of a numerical wave tank for analysis of nonlinear and irregular wave field. Fluid Dynamics Research 8, 231-251.
16. Tanizawa, K., 1995. A nonlinear simulation method of 3-D body motions in waves (1st Report). Journal of the Society of Naval Architect Japan 178, 179-191.
17. Tanizawa, K., 1996. Long time fully nonlinear simulation of floating body motions with artificial damping zone. Journal of the Society of Naval Architects of Japan 180, 311-319.
18. Tanizawa, K., 2000 The state of the art on numerical wave tank. In: Proceedings of 4th Osaka Colloquium on Seakeeping Performance of Ships 2000, pp.95-114.
19. Weng, W.K., Chou, C.R., 2007. Analysis of response of floating dual pontoon structure. China Ocean Engineering 20(1), 91-104.
20. Williams, A.N., Abul-Azm, A.G., 1997. Dual pontoon floating breakwater. Ocean Engineering 24(5), 465-478.
21. Yamamoto, T., Yoshida, A., Ijima, T., 1980. Dynamics of elastically moored floating objects. Applied Ocean Research 2(2), 85-92.
22. Yamamoto, T., 1981. Moored floating breakwater response to regular and irregular waves. Applied Ocean Research 3(1), 27-36.
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