為了因應與日俱增的能源需求及對於再生能源開發的全球趨勢，擁有黑潮能源流經的台灣也開始致力於海洋能源的開發。然而台灣海洋能源開發技術剛起步而尚未成熟，尤其沒有在大水深環境下錨碇海流發電機之經驗，這類系統之性能及運作情形也還有待釐清，此外，由於大水深條件下安裝機組的成本的成本會大幅提高，因此，建立適當的模擬與分析工具以及設計可同時搭載多台發電機的浮式平台實有其必要。
本研究主要分為兩部分，其一為單一導流罩式發電機安裝在較低海床上的研究，配合計算流體力學(Computational Fluid Dynamics: CFD)軟體 ANSYS-FLUENT進行噴射型導流罩(Nozzle duct type generator ; duct)的流體係數計算，並搭配在海洋油氣開發領域應用上相當成熟的模擬軟體OrcaFlex，建立其系纜系統及其重心擺放之設計以模擬發電機在一般波浪條件及颱風浪條件下的運動情況。其二則是為多個導流罩式發電機安裝於本研究設計之浮式Spar平台的研究，藉由使用外海結構設計軟體ANSYS-Aqwa進行平台的設計，同時搭配OrcaFlex建立整體平台系纜及平台牽引發電機之纜繩模擬，以了解在颱風浪條件下的spar及導流罩在六個自由度變化。

In the response of the increasing energy demand and the global trend in renewable energy development, finding the way to harvest Kuroshio current energy which flows through the east coast of Taiwan is an important project. However, due to the high-water depth at east side of Taiwan, developing an ocean current energy harvest platform is the imperative issue. Taiwan is lack of the analysis, design and field experiences in offshore engineering including mooring line deployment. Therefore, establishing a feasible mooring line and anchor system for installing the proposed nozzle-diffusor duct type current power generator (duct) at the deep-water environment is necessary. Moreover, to reduce the unit installing cost of the duct and keep a better energy capturing efficiency, a Single Point Anchoring Reservoir (SPAR) type platform which is a floating platform frequently used in the offshore drilling industry was established.
In this study, Computation Fluid Dynamics (CFD) software ANSYS-FLUENT was used to calculate the hydrodynamic coefficients including drag and added mass of the duct. By collaborating these data into OrcaFlex software which is the leading software in mooring line design, the simulation of single duct anchored on the seabed was established. The results of the duct facing storm wave and normal wave condition was obtained. The possible high Power Take Off (PTO) results was gained in normal wave condition. Meanwhile, the relationship between center of gravity position and the pitching angle of the duct was verified. Another software ANSYS-Aqwa was used to design Spar platform for carrying multiple ducts. By collaborating Solidworks software, a platform followed the design code from ABS Rules with stable 6 degree of freedoms Response Amplitude Operators (RAO) of the spar was designed. The designed spar model was established in OrcaFlex and the mooring line system including the anchor chain and duct chain were built. The time domain results in OrcaFlex shows a high stability of the spar under storm wave condition. Although the high PTO was only found in 90° storm waves tests, both ducts were very safe instead of colliding to in other storm waves tests.

CHINESE ABSTRACT.........................................................................i
ABSTRACT..........................................................................................ii
DEDICATION......................................................................................iv
ACKNOWLEDGEMENT......................................................................v
TABLE OF CONTENTS.....................................................................vi
LIST OF FIGURES...........................................................................viii
LIST OF TABLES..............................................................................xii

I INTRODUCTION.......................................................................1
1.1 Overview....................................................................................1
1.2 Kuroshio Current.......................................................................3
1.3 Offshore Floating Platform........................................................4
1.4 Literature Review......................................................................6
1.5 Objectives and Scope.............................................................10

II METHODOLOGY....................................................................12
2.1 ANSYS Fluent.........................................................................12
2.2 ANSYS Aqwa..........................................................................15
2.3 OrcaFlex.................................................................................19

III ADDED MASS AND DRAG COEFFICIENTS.........................28
3.1 Added Mass Theory................................................................29
3.2 Translational Motion................................................................32
3.3 Rotational Motion....................................................................34

IV SINGLE GENERATOR ANCHORED ON THE SEABED........38
4.1 System Configuration..............................................................38
4.2 Determination of Mass............................................................41
4.3 Response to Waves and Current............................................44
4.4 Summary.................................................................................49

V DESIGN OF SPAR PLATFORM.............................................51
5.1 Preliminary Testing by ANSYS Aqwa.....................................51
5.2 Design Procedure of Platform................................................54
5.3 Response to Waves...............................................................63

VI MULTIPLE GENERATORS ON SPAR...................................66
6.1 System Configuration.............................................................67
6.2 Motion of Platform..................................................................75
6.3 Motion of Generators..............................................................79

VII CONCLUSIONS.....................................................................88
7.1 Concluding Remarks..............................................................88
7.2 Recommendations for Future Studies....................................89

REFERENCES...............................................................................91

APPENDIX A..................................................................................94
APPENDIX B..................................................................................95
APPENDIX C..................................................................................98
APPENDIX D................................................................................103
APPENDIX E................................................................................108
APPENDIX F.................................................................................113
APPENDIX G................................................................................118
VITA..............................................................................................121

ABS. (2014). Floating Production Installations. American Bureau of Shipping, Houston TX, USA.

Bedard, R. (2006). Overview: EPRI Ocean Energy Program, The Possibilities in California. Electric Power Research Institute, California.

Chakrabarti, S. K. (1987). Hydrodynamics of Offshore Structures. WIT press., London, UK.

Chen, B. F., Tian, W. M., Leu, S. S., Tai, C. H., Giang, Z. L., Lu, S.Y. (2011-2013). A study on Kuroshio power development Penghu case. NSC101- 3113-E-110-003.

Chen, B. F., and Huang, C. W. (2016). Nozzle and Diffuser in Drifting Horizontal Turbine Flow. Proceedings of the 26th International Ocean and Polar Engineering Conference. International Society of Offshore and Polar Engineers.

Chen, F. (2010). Kuroshio Power Plant Development Plan. Renewable and Sustainable Energy Reviews, 14(9), 2655–2668.

Chen, Y.-Y., Hsu, H.-C., Bai, C.-Y., Yang, Y., Lee, C.-C., Cheng, H.-K., Shyue, S.-W., Li, M.-S., and Hsu, C.-J. (2016). Evaluation of Test Platform in the Open Sea and Mounting Test of KW Kuroshio Power-Generating Pilot Facilities. Proceedings of the 2016 Taiwan Wind Energy Conference. (in Chinese)

Chuang, C.-C. (2016). Experiment Study of the Motion of the Floating Offshore Turbine. Master Thesis, National Cheng Kung University, Taiwan.

Grove, M. A., Conceição, C. A. L., and Schachter, R. D. (2003). A Concept Design and Hydrodynamic Behavior of a Spar Platform. Proceedings, OMAE (Vol. 37166, pp. 8–13).

Huang, C.-W. (2016). Optimal Design of a Nozzle and Diffuser Duct. Master Thesis, National Sun Yat-sen University, Taiwan.

Jacobson, M. Z., and Delucchi, M. A. (2011). Providing All Global Energy with Wind, Water, and Solar Power, Part I: Technologies, Energy Resources, Quantities and Areas of Infrastructure, and Materials. Energy policy, 39(3), 1154–1169.

Kyu, S. P. (2013). Fatigue Performance of Deep Water Steel Catenary Riser. Master Thesis, Pohang University of Science and Technology.

Lin, H.-Y. (2015). Simulation on the Deployment and Recovery of a Floating Kuroshio Turbine. Master Thesis, National Taiwan University, Taiwan.

Li, B. B., Ou, J. P., and Teng, B. (2010). Stability and Hydrodynamic Analysis of a Deep Draft Multi-Spar Platform. The Ocean Engineering (Haiyang Gongcheng), 28(2), 8–14.

Lo, H,-Y. (2017). Dynamic Analysis of Current Turbine System. Master Thesis, National Taiwan Ocean University, Taiwan.

Mansouri, R. and Hadidi, H. (2009). Comprehensive Study on the Linear Hydrodynamic Analysis of a Truss Spar in Random Waves. World Academy of Science, Engineering and Technology, 53, 930–942.

Mekha, B. B., Johnson, C. P., and Roesset, J. M. (1995). Nonlinear Response of a Spar in Deep Water: Different Hydrodynamic and Structural Models. Proceedings of the Fifth International Offshore and Polar Engineering. International Society of Offshore and Polar Engineers.

Minesto, Deep Green Technology. [cited 2017; Available from: https://minesto.com/]

Ketabdari, M. J. and Mirzaei Sefat, S. (2011). Dynamic Analysis of Interaction between Linear Waves and Spar Floating Platform. Civil Engineering Infrastructures Journal, 45(1), 45–52.

NEDO, New Energy and Industrial Technology Development Organization. [cited 2017; Available from: http://www.nedo.go.jp/english/news/AA5en_100269.html]

OrcaFlex Manual. Version 10.0b ed.: Orcina Ltd.

Kurian, V. J., Ng, C. Y., and Liew, M. S. (2013). Dynamic Response of Truss Spar Due to Wave Actions. Research Journal of Applied Sciences, Engineering and Technology, 5(3), 812–818.

Xfoil Drela, M. XFOIL-Subsonic Airfoil Development System. [cited 2017; Available from http://web.mit.edu/drela/Public/web/xfoil/]

Yang, M., Teng, B., Ning, D., and Shi, Z. (2012). Coupled Dynamic Analysis for Wave Interaction with a Truss Spar and Its Mooring Line/Riser System in Time Domain. Ocean Engineering, 39, 72–87.

Zhang, F., Yang, J. M., Li, R. P., and Liu, C. G. (2008). Research on the Concept Design of Spar Platform. The Ocean Engineering, 26(2), 1–10.

Zhang, Y., Shen, H., Dai, F., Ni, T., and Zhuang. J. (2013). Hydrodynamic Characteristics of Cylindrical Semi-Submersible Offshore Oil Platform. Journal of Jiangsu University, 1, 006.