本文利用三維源點分佈法，來求解三體船在波浪中前進時的非線性流體動力。非線性流體動力由附加阻力(Added resistance)及橫向漂流力(Mean lateral drifting force)所組成，其為船體運動、輻射力、繞射力及入射波影響的結果。假設流體為非旋性、不可壓縮且為無黏性的理想流體，探討頻率領域中，三體船在規則波中之運動及非線性流體力。
運用小板法及源點分佈法，配合物體表面邊界條件，來解析、計算船體表面所承受之流體力，進而求得三體船之船體運動。根據Salvesen求解非線性力的方法，將已得到的船體運動及各種流速勢加以計算，則可求出三體船之附加阻力及橫向漂流力。
本論文將數值分析之結果與實驗值做比較，來驗證數值方法分析之正確性，並將穩態項、不同入射波波向以及不同副船體配置的影響加入考慮，來預估三體船在波浪中航行時的附加阻力和橫向漂流力，從比較結果可看出本方法預估附加阻力及橫向漂流力已有相當不錯的結論。

In the paper the three-dimensional source distribution method is applied to solve the nonlinear hydrodynamic forces on the trimaran ship advancing in waves. The nonlinear forces can be divided into two components, i.e. added resistance and lateral drifting force, which are caused by ship motions, radiation force, diffraction force and Froude-krylov force. The fluid considered here are assumed to be irrotational, incompressible and non-viscous and the solutions of the nonlinear hydrodynamic forces are treated in frequency domain.
Using the panel method and source distribution method, the related hydrodynamic coefficients can be calculated by the boundary conditions and the ship motions can be solved. Based on the Salvesen’s method, the added resistance and lateral drifting force will be obtained from the ship motions and corresponding potentials. In the paper, the steady flow is also included to check the effect on the nonlinear forces with the different wave headings and different side-hull arrangements. From the comparisons of the theory and experiment, we find that the present technique can well predict the added resistance and lateral drifting force for the trimaran ship advancing in waves.

[1]Alexander E. Bingham ＆ John K. Hampshire, “Motions and Loads of a Trimaran Traveling in Regular Waves”, UK, FAST 2001 September Southampton.
[2]Benjamin B. Ackers & Thad J. Michael, “An Investigation of the Resistance Characteristics of Powered Trimaran Side Hull Configurations”, SNAME Trans.105, pp. 349-373, 1997.
[3]Brard,R.,“the Representation of a Given Ship Form by Sigularity Distributions When the Boundary Condition on the Free Surface is linearized”, Journal of Ship Research,Vol. 16,No. 2,pp. 79-92,March 1972.
[4]Chou, S. K. & Chang, F. N.,“Study on Resistance Prediction of High-Speed”, International Forum on Systems and Mechatronics, 2006.
[5]Dalzell, J. F. and Kim, C. H.,“An Analysis of the Quadratic Frequency Response for Added Resistance”, Journal of Ship Research, 23(3), Sept. 198-208,1979.
[6]Dario Bruzzone and Paola Gualeni,“The prediction of seakeeping performance and added resistance in the design of multi-hull vehicles”,9th Symposium on practical design of ships and other floating structure,2004.
[7]Duan, W. Y.,“Comparison of Two Seakeeping Prediction Methods for High Speed Multi-Hull Vessels”, Southampton, UK, FAST 2001 September.
[8]Ermina Begovic,“Seakeeping Assessment of Trimaran Hulls”, FAST October, 2003 Ischia ITALY.
[9]Fang, C. C. & Wu, C. H., “Parametric Study on Motions of a High Speed Trimaran Travelling in Oblique Wave”, International Forum on Systems and Mechatronics, 2006.
[10]Fang, M. C.,“ Second-order steady forces on a ship advancing in waves”, Int. Shipbuild. Progr., 38(413), 73-93,1991.
[11]Fang, M. C., Lee, M. L. and Lee, C. K.,“Time Simulating of Water Shipping for a Ship Advancing in Large Longitudinal Waves”, Journal of Ship Research, Vol.37, No.2, pp.126-137, 1993.
[12]Fang, M. C. and Chen, G. R,“On the nonlinear hydrodynamic forces for a ship advancing in waves”, Ocean Engineering, Vol. 33, pp.2119-2134,2006.
[13]Farell C.,“On the Wave Resistance of a Submerged Spheroid”, Journal of Ship Research, Vol 17, No.2, pp72-79,1973.
[14]Guevel, P. and Bougis, J. ,“Ship Motions with Forward Speed in infinite depth”,International Shipbuilding Progress, Vol. 29,pp 103-117, 1982.
[15]Haskind M. D., “The Hydrodynamic Theory of Ship Oscillation in Rolling and Pitching”, Bulletin de I`Academie des Sciences de I`URSS, Classe des Sciences Techniques, No.1, pp.23-34,1946;,SNAME Technical and Research Bulletin No.1-12, Traslated by SNAME 1953.
[16]Haskind M. D.,“The Oscillation of a Ship in Still Water”, Prikladnaya Matematika I Mekhanika, Vol. 10, No.1, pp.33-66, 1946; SNAME Technical and Research Bulletin No.1-12, Traslated by SNAME 1953.
[17]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.
[18]Kim C. H., Chou F. S. and Tien D.,“Motions and Hydrodynamic Load of a Ship Advancing in Oblique Waves”, Transcations of the Society Of Naval Architects and Marine Engineers, Vol.88, pp.225-256, 1980.
[19]Lin, W. C. and Reed, A. M.,“The second –order steady forces and moment on a ship moving in an oblique seaway”, 11th Symp. On Naval Hydrodynamics, London,1976.
[20]Luca Sebastiani & Roberta Depascale, “Design Project of a Trimaran Multipurpose - Study of the Hydrodynamic Aspects”, FAST October, 2003 Ischia ITALY.
[21]Maruo Hajime,“The Excess Resistance of a Ship in Rough Seas, International Shipbuilding Progress”, 4(35), July 1957.
[22]Maruo, H.,“The drift of a body floating on waves, Journal of Ship Research”, 4(1), 1-10,1960.
[23]Maruo, H. and Iwase, K.,“Calculation of Added resistance in Oblique Waves”, J. Soc. N.A. Japan, 147, (in Japanese),1980.
[24]Newman, J.N.,“The second-order time-average vertical force on a submerged body moving beneath a regular wave system”, unpublish,1970.
[25]Salvesen N., Tuck, E.O. and Faltinsen O.,“Ship Motion and Sea Load”, Transcation of the Society of Naval Architects and Marine Engineers, Vol.78, 250-287, 1970.
[26]Salvesen, N.,“Second-order steady-state forces and moments on surface ships in oblique regular waves”, Int. Symp. On Dynamics of Marine Vehicles and Structures in Waves, Univ. College, London,1974.
[27]Salvesen, N.,“Added resistance of ships in waves”, Journal Of Hydronautics,12(1), 24-34,1978.
[28]Shen, H. T. and Farell,C. ,“Numerical Calculation of the Wave Integrals in the Linearized Theory of Water Waves”, Journal of ship Research,Vol. 21,No. 1,pp. 1-10,March 1977.
[29]Stefano & Marco Capasso,“Effect of Hulls Form Variations on the Hydrodynamic Performances in Waves of a Trimaran Ship”, FAST October, 2003 Ischia ITALY.
[30]Storm-Tejsen, J., Yeh, H.Y.H. and Moran, D.D.,“ Added resistance in waves”,Trans. SNAME, 81, 109-143,1973.
[31]Takagi, K.,“Simplified Formulas for the Calculation of Added Resistance, Steady Lateral Force and Turning Moment in Waves”. J. Kansal Soc. N.A., Japan, 216. (in Japanese),1991.
[32]Telste J. G. and 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.
[33]Wehausen J. V. and Laitone C. V.,“Surface Waves”, Handbuck der physik, Vol.9, Spring Verlag, Berlin, 1960.
[34]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。
[35]胡登凱，“波浪中三體船之穩態及非穩態之流體動力解析”，國立成功大學系統及船舶機電工程研究所論文，中華民國九十六年六月。
[36]涂耕岳，“波浪中三體船運動之三維分析”，國立成功大學系統及船舶機電工程研究所碩士論文，中華民國九十三年六月。
[37]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碩士論文，中華民國八十六年六月。
[38]陳澤胤，“三體船波浪負荷之三維分析”，國立成功大學系統及船舶機電工程研究所碩士論文，中華民國九十四年六月。
[39]廖培元，“波浪中船體運動之三維解”，國立成功大學造船暨船舶機械工程研究所碩士論文，中華民國八十七年六月。
[40]蘇森熙，“以小板法解析潛體在自由液面下之繞射問題”，國立成功大學造船工程研究所碩士論文，中華民國八十五年六月。