本文是採用三維脈動型源點配合小板法作為基礎來解析雙體船之間的入射、繞射及輻射問題，進而求解雙體船在流場中所產生的壓力，並將得到的壓力利用座標轉換的方式，加入相位角的觀念，推導出雙體船的各項流體動力係數，以求解雙體船之六度運動量。由於本文的方法只須計算單一船體的流體動力係數再加以轉換，即可得到雙體船在兩船體間無交互作用情況下之流體動力係數，進而求得雙體船的運動量，因此對於有考慮兩船體間交互作用影響的計算方式而言，本文所推導出的方法可有效地節省計算時間及計算機資源。
本文將分別對NPL雙體船、小水面雙體船、半潛式鑽油平台及SSP等四種船型進行理論分析。而在小水面雙體船方面，亦加入了黏性阻尼效應及穩定翼效應來求解修正後得到的運動量。首先以一般的三維源點分佈理論值與本文計算的結果來進行比較，並以本文所得到的三維相位轉換法的結果與二維相位轉移法的結果及以往相關的實驗結果進行比對，來驗證本文相位轉移法的準確性。最後再利用不同的入射波角、船體間距與速度，來探討雙體船兩船體間交互作用的影響，以達到相位轉移法應用之最佳實用性。

The present paper presents the source distribution method with the three dimensional pulsating source to analyze the corresponding hydrodynamic problems for the catamaran ship in waves. The phase transfer method is applied to simplify the six degrees of freedom motion prediction, which neglects the interaction between two hulls. In the present method, only the related hydrodynamic coefficients for the monohull are calculated and the phase transfer for each hull of the catamaran ship are then considered. Consequently the computation time can be saved because of neglecting the interaction effect between two hulls.
In order to investigate the validity of the present technique, four models, i.e. NPL catamaran ship, SWATH 6A ship, Semi-submersible platform and SSP models are selected for the calculations. Because of the characteristics of the small water plane, the viscous damping effect must be considered in the calculation of the SWATH ships. Besides, the fin stabilizer effects are al so included for the SWATH ships. From the results of the theoretical and experimental comparisons, we find that the present three dimensional phase transfer method indeed has its advantage in some respects and can be applied to some hydrodynamic researches for twin-hull structures in waves. However some limitations for the speed and clearance between two hulls must be carefully concerned.

1. Centeno, R., Varyani, K.S., and Guedes Soares, C., “Experimental Study on the Influence of Hull Spacing on Hard-Chine Catamaran Motions”, Journal of Ship Research, Vol.45, No.3, pp.216-227, 2001.
2. Fang, M.C., “A Study of Hydrodynamic Interactions of Two Ships in the Open Seas”, Stevens Inst. of Tech. PH.D. Dissertation, 1984.
3. Fang, M.C., “The Motions of SWATH Ships in Waves”, Journal of Ship Research, Vol.32, No.4, pp.238-245, 1988.
4. Faltinsen, O., Hoff, J.R., Kvalsvold, J., and Zhao, R., “Global Wave Loads on High-Speed Catamarans”, Proceedings, Elsevier Applied Science, London and New York, No.1, pp.1360-1375, 1992.
5. Fang, M.C. and Lin, B.N., “The Analysis of the Effect of Stabilizing Fin on SWATH Ship in Waves”, JSNAME, NSC-82-0403-E006-275, pp.41-56, 1994.
6. Fang, M.C. and Shyu, W.J., “The Improved Prediction for Hydrodynamic Characters of SWATH Ship in Waves”, Proc. Of National Science Council, Vol.18, No.5, pp.495-507, 1994.
7. Hess, J. L. and Smith, A. M. O., ”Calculation of Nonlifting Potential Flow About Arbritrary Three-Dimensional Bodies”, Journal of Ship Research, Vol. 8, No.2, pp 22-44,1964.
8. Hong, Y.S., “Improvements in the Prediction of Heave and Pitch Motions for SWATH Ships”, DTNSRDC Report, SPD-0928-02, 1980.
9. Kim, C.H., Chou, F.S. and Tien, D., “Motions and Hydrodynamic Loads of a Ship Advancing in Oblique Waves”, SNAME Trans., Vol.88, pp.225-256, 1980.
10. Kim, C.H. and Bao, W., “A Strip Method for Lateral Drift Force of a Semisubmersible”, Stevens Inst. of Techn., DCOE., Hoboken,N.J. 07030. pp.260-265, 1985.
11. Lee, C.M., ”Prediction of Motion, Stability, and Wave Load of Small-Waterplane-Area, Twin-Hull Ships”, SNAME Trans., Vol.85, pp.94-130, 1977.
12. Pinkster, J.A., “Low Frequency Second Order Wave Exciting Forces on Floating Structures”, Publication No.650, Netherlands Ship Model Basin, Wageningen, Netherlands.
13. Shen, H.T. & Farell, C., “Numerical Calculation of the Water Integrals in the Linearized Theory of Water Wave”, Journal of Ship Reseach, Vol.21 ,No.1, pp.1-10, 1977.
14. Telste, J.G. & Noblesse F., “Numerical Evaluation of the Green Function of Water-Wave Radiation and Diffraction”, Journal of Ship Research, Vol.30, No.2, pp.69-84, 1986.
15. Van’t Veer, A.P. and Siregar, F.R.T., “the Interaction Effects on a Catamaran Travelling with Forward Speed in Wave”, Proceedings, FAST95, Lubeck, Germany, No.1, pp.87-98, 1995.
16. 方銘川, “小水面雙體船在波浪中附加阻力之預測”, 行政院國家科學委員會專題研究計畫成果報告, 中華民國七十九年七月三十一日.
17. 李文華, “波浪中雙體船運動之三維分析”， 國立成功大學造船暨船舶機械工程研究所碩士論文, 中華民國八十九年六月.
18. 林翰屏, “以小板法求解航行船舶之輻射問題”, 國立成功大學造船工程研究所碩士論文, 中華民國八十六年六月.
19. 陳榮元, “波浪中航行船舶所受激盪力之三維解”, 國立成功大學造船工程研究所碩士論文,中華民國八十六年六月.
20. 郭柏志, “穩態勢流對雙體船運動之影響”， 國立成功大學造船暨船舶機械工程研究所碩士論文,中華民國九十一年六月.
21. 劉怡, “以簡化法解波浪中雙體結構物之流體動力問題”，國立成功大學造船及船舶機械工程研究所碩士論文,中華民國八十五年六月.
22. 蘇森熙, “以小板法解析潛體再自由液面下之繞設問題”,國立成功大學造船工程研究所碩士論文,中華民國八十五年六月.