• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.55-61
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• 2003

The maneuvering equations of motion are derived to express the motion of a ship. The wave forces in the time domain analysis are generated from the frequency transfer function calculated by 3-D source distribution method. The linear wave forces whose periods are equal to those of incident waves and the nonlinear wave forces that make long period drift forces are computed for the simulation. The consideration of irregular waves and nonlinear wave force effects on the slew motion are carried on the analyzing the motion of ship in the regular and irregular waves.

• Journal of Ocean Engineering and Technology
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• v.8 no.2
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• pp.31-37
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• 1994

3-Dimensional panel method is now developed to the level that one can calculate the lift of a three dimensional body with the same accuracy of wind tunnel test and some current codes can consider the boundary layer effects due to the viscosity and unsteady motion in the calculation of lift. This paper is also aimed to develop these kinds of computing programs, and as a beginning, the authors restricted the problems to the steady potential flow cases. The calculation of 3-Dimensional body, wing and tandem wing carried out, using source panel and vortex ring panel. Finally, the interactions between 3-Dimension symmetric body and a wing are also calculated.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.180-184
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• 2001

본 연구에서는 반잠수식 Rig의 형상에 따른 최적 형상을 검토하기 위하여 최근 건조되고 있는 4-Column과 2-Lowhull 을 가진 원통형 Column과 4각 Column형을 공시모형으로 택하여 규칙파중 두 구조물에 작용하는 유체력과 유체력에 의한 운동 응답을 계산, 형상에 따른 유체 역학적 특성과 동요 진폭의 관계를 검토하였다. 수치계산은 3차원 특이점 분포법을 이용하여 정상상태에 대하여 실행하였다. 구조물의 형상과 역학적인 간섭의 영향을 이용, 보다 성능이 우수한 형상을 얻을 수 있음을 확인하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.193-199
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• 2013

Course keeping ability of ships under wave are analyzed with wave. The simulation with three degrees of freedom is developed and 3-D source distribution method is applied to get wave force for the simulation. The simulation is conducted with the restriction of maximum rudder angle and time delay of control and regular wave and irregular wave are considered as the source of external forces. Simulations with ships which have different maneuverability with tuned hydrodynamic coefficients are developed to assess the variation of the course keeping ability depending on the ship's maneuvering characteristics. The course Keeping ability is evaluated by comparison of distance while the ships are simulated with autopilot control.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.150-161
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• 1996

A numerical procedure is described for predicting steady drift forces on very large offshore structures supported by a large number of the floating bodies of arbitrary shape dimensional source distributing method, the wave interaction theory, the far-field method of using momentum theory and the finite element method for structurally treating the space frame elements. Numerical results are compared with the experimental or numerical ones, which are obtained in the literature, of steady drift forces on a offshore structure supported by the 33(3 by 11) floating composite vertical cylinders in waves. The results of comparison confirmed the validity of the proposed approach.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.73-81
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• 1994

The source and source/dipole distribution methods using 3-dimensional panel method have been widely used for ship motion analysis. When these methods are used, large errors in the predicted hydrodynamic coefficients are introduced around the irregular frequencies caused by the resonance of imaginary internal flow. Therefore, the irregular frequencies need to be removed for an accurate prediction of ship motion. This paper adopts 3-dimensional translating and oscillating Green function derived by Wu. The adaptive integration method, stretching transform and stationary phase method are used for the calculation of the calculation of Green function and the integral equation is derived by distributing the Green function n ship surface and inner free-surface. The condition of zero normal velocity, that is, wall condition on inner free-surface has been successfully used for the removal of irregular frequencies in oscillating problems. The calculations are carried out for series 60($C_B=0.7$) vessel and the results are compared with those of other theoretical analyses and experiment.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.64-71
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• 2011

The Tension Leg Platform(TLP) is restrained from oscillating vertically by tethers(or tendons), which are vertical anchor lines tensioned by the platform buoyancy larger than the platform weight. Thus a TLP is a compliant structure which allows lateral movements of surge, sway, and yaw but restrains heave, pitch, roll. In this paper, the motions of a TLP in current and waves were investigated. Hydrodynamic forces and wave exciting forces acting on the TLP were evaluated using the three dimensional source distribution method. The motion responses and tension variations of the TLP were analyzed in the case of including current or not including one in regular waves and effects of current on the TLP were investigated.

• Journal of Power System Engineering
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• v.14 no.2
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• pp.48-54
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• 2010

An improved numerical scheme, to which the hydroelastic method is adapted, is introduced for predicting the motion and structural responses of tension leg platforms(TLPs) in regular waves. The numerical approach in this work is based on a combination of the three dimensional source distribution method and the finite element method. The hydrodynamic interactions among TLP members, such as columns and pontoons, are included in the motion and structural response analysis. The drag forces on the submerged slender members, which are proportional to the square of relative velocity, are included in order to estimate the responses of members with better accuracy. Comparisons with other results verify the works in this paper.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.76-89
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• 1997

The hydrodynamic interaction characteristics between multiple floating bodies of semisubmersible type are examined to present the basic data for the design of huge offshore structures supported by a large number of the floating bodies in multi-directional irregular waves. The numerical approach is based on a combination of a three-dimensional source distribution method, the wave interaction theory and the spectral analysis method. The effects of wave directionality on the wave exciting forces acting on multiple floating bodies in multi-directional irregular waves also have been pointed out.

• Journal of Ocean Engineering and Technology
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• v.7 no.1
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• pp.133-146
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• 1993

A numerical procedure is described for predicting the motion and structural responses of tension leg platforms (TLPs) in waves. The developed numerical approach is based on combination of a three dimensional source distribution method and the dynamic response analysis method, in which the superstructure of TLPs is assumed flexible instead of the rigid body assumption used in usual two-step analysis method, proposed by Yoshida et. al. .The hydrodynamic interactions among TLP members, such as columms and pontoons, are included in the motion and structural analyses. Numerical results are compared with the experimental and numerical ones, which are obtained in the literature, of the motion and structural responses of a TLP in waves. The results of comparison confirmed the validity of the proposed approach.