• Title/Summary/Keyword: High Speed Catamaran

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A Potential-Based Panel Method for the Analysis of Resistance Characteristics of a High Speed Catamaran (포텐셜기저 패널법에 의한 고속쌍동선의 저항성능 해석)

  • Kim, Y.G.;Rhyu, S.S.;Yoo, J.H.;Lew, J.M.;Hong, S.K.
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.4
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    • pp.12-20
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    • 1997
  • A potential-based panel method has been developed to investigate the resistance characteristics of a high speed catamaran advancing on the free surface. Normal dipoles and sources are distributed on the body surface while sources are distributed on the free surface. Linearised free surface conditions are used in the present analysis. To avoid the instabilities due to the velocity difference between inner and outer flow of a high speed catamaran, Kutta condition has been applied at the stern. Model test has been carried out not only to validate the numerical results but to confirm the capabilities of a CWC(Circulating Water Channel). It is believed that we can obtain the qualitatively reasonable results in the CWC. Computed results are compared with those of experiments and Insel's experimental values. Since the Kutta condition is applied at the stern, stable solutions are obtained at the high speed range. The present method, using linearised free surface conditions at the high speed range, seems to be a useful tool in the hull form design of a high speed catamaran.

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Attitude Control Tests for a High Speed Catamaran in Regular Head Waves (고속 카타마란선의 규칙 정면파중 운항자세 제어 시험)

  • C.G. Kang;S.Y. Hong;S.H. Suh;C.M. Lee;Y.G. Kim;I.Y. Gong
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.2
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    • pp.36-43
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    • 1996
  • An Attitude Control System for a high speed catamaran with contorl fins in waves is designed and investigated by the experimental methods. An optimal control theory is applied to design the automatic attitude control system of the high speed catamaran for its good seaworthiness. The experimental results performed in KRISO model basin for the displacements and accelerations for the model ship are measured in regular hear waves. Form the epxerimental results the effect of control planes is thought to be incroeasing with speed.

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Computation of Flows Around a High Speed Catamaran

  • Kwag, Seung-Hyun
    • Journal of Mechanical Science and Technology
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    • v.15 no.4
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    • pp.465-472
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    • 2001
  • A numerical study is carried out to clarify the characteristics of flow fields and breaking phenomena around a high speed catamaran hull advancing on calm water. Computations are carried out for Froude numbers between 0.2 and 1.0 and for ratios of the distance between hulls to the catamaran length varying between 0.2 and 0.5 for a mathematically defined Wigley hull. A Navier-Stokes solver which includes the nonlinearities of free surface conditions is employed. Computations are performed in a rectangular grid system based on the Marker & Cell method. For validation, present computation results are compared with existing experimental results. As an application, the results of the displacement catamaran are used for the breaking analysis.

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A study on the motion characteristics of a high-speed catamaran (고속쌍동선의 운동특성에 관한 연구)

  • Oh, Il-Geun
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.116-123
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    • 1997
  • 세계적으로 수요가 증대하고 있는 고속선의 설계시 승선감 또는 내항성은 필수적으로 고려되어야 하는 중요요소이다. 고속선은 필연적으로 과도한 운동을 동반하며 그로 인해 승객들은 극심한 멀미와 구토 등 불쾌한 승선감을 경험하게 된다. 근래에 항공 및 육상 교통수단들의 고급화에 따라 해양 운항선사들도 선박품질의 고급화와 괘적한 승선감 확보에 비상한 관심을 보이며 승객 유치 및 승선률 제고를 도모하고 있다. 본 논문은 고속쌍동선에 대한 내항성능을 추정하고 그 해석결과를 실험과 비교하였다. 상하동요 및 종동요 간의 선형 연성 운동방정식을 사용하였고, 규칙파에 대한 상하동요의 응답특성 곡선을 구하였다. 또한 불규칙파에 대한 운동응답을 추정하기 위하여 ITTC파도 스펙트럼을 적용하였으며, 본 고속쌍동선의 운동성능에 미치는 선수 및 선수각의 영향을 고찰하였다.

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Marine Analysis of WIG (Wing in Ground) and High Speed Catamaran

  • Kwag, Seung-Hyun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2000.06a
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    • pp.107-114
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    • 2000
  • Marine analysis was made to investigate the hydrodynamic effects of a Wing in Ground (WIG) by means of finite difference techniques. The air flow field around WIG is analyzed by the Marker & Cell (MAC) based method, and the interaction between WIG and the free surface are studied by showing pressure distributions above the free surface. In the latter part, computations are extended to make clear the flow characteristics of a high speed catamaran in the rang of Froude numbers 0.2 to 1.0 with a separation to length ratios of 0.2, 0.3 and 0.5. The Navier-Stokes solver is invoked in which the nonlinear free-surface boundary condition is applied. For the validation, computational results are compared with the experiments.

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Numerical Study on Wave Resistance of a High Speed Catamaran (고속 카타마란의 조파저항 수치연구)

  • 곽승현
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.04a
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    • pp.29-34
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    • 2000
  • This paper describes a numerical study to make clear the characteristics of flow around a high speed catamaran hull advancing on calm water. The simulation is carried out at Froude number of 0.5 with a separation to length rations of 0.2 to 0.5. To simulate the flows, the Navier-Stokes solver is employed in which the free surface condition is included. Computations are performed in a rectangular grid system based grid system based on the Marker & Cell method. For the validation, the computation results are compared with the experiments.

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Numerical Study on Sub-Breaking of Free Surface Viscous Flow (자유표면 점성 유동의 준쇄파 수치연구)

  • Kwag, Seung-Hyun
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.226-231
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    • 2003
  • The viscous interaction of stern wave is studied by simulating the free-surface flows, including sub-breaking phenomena around a high speed catamaran hull advancing on calm water. The Navier-Stokes equation is solved by a finite difference method where the body-fitted coordinate system, the wall function and the triple-grid system are invoked. The numerical appearance of the sub-breaking waves is qualitatively supported by the experimental observation They are also applied to study precisely on the stern flow of S-103 as to which extensive experimental data are available. For the catamaran, computations are carried out for the mono ana twin hulls.

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Calculation of Wavemaking Resistance of High Speed Catamaran Using a Panel Method

  • Lee, Seung-Joon;Joo, Young-Ryeol
    • Journal of Hydrospace Technology
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    • v.2 no.2
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    • pp.36-43
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    • 1996
  • In this work, a panel method is described, which cart solve the flow field round a surface-piercing body that experiences lift and wave resistance. As the body boundary condition, a Dirichlet type is employed, and as the free surface boundary condition the Poisson type is implemented, while in its discretization Dawson's 4-point upwind difference scheme is utilized, and as the Kutta condition a Morino-Kuo type is chosen. As to the type of singularity, source panels are distributed on the free surface, and source and dipole panels on the body surface, and dipole panels on the wake surface. For a sample run, a catamaran of the parabolic Wigley hull is chosen, for which experimental data are available, and the predictions by the numerical means and by the experiment are compared for a wide range of parameters.

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The overall motion sickness incidence applied to catamarans

  • Piscopo, Vincenzo;Scamardella, Antonio
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.4
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    • pp.655-669
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    • 2015
  • The Overall Motion Sickness Incidence is applied to the hull form optimization of a wave piercing high-speed catamaran vessel. Parametric hull modelling is applied to generate two families of derived hull forms, the former varying the prismatic coefficient and the position of longitudinal centre of buoyancy, the latter instead the demi-hull separation. Several heading angles are analysed in a seaway, considering all combinations of significant wave height and zero-crossing period under two operating scenarios. The optimum hull is generated and vertical accelerations at some critical points on main deck are compared with the parent ones. Finally a comparative analysis with the results obtained for a similarly sized monohull passenger ship is carried out, in order to quantify, by the OMSI, the relative goodness in terms of wellness onboard of monohulls and catamarans, as a function of sea states and operating scenarios.