• Title/Summary/Keyword: Second-order mean drift force

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Performance Prediction of an OWC Wave Power Plant with 3-D Characteristics in Regular Waves

  • Hong, Do-Chun;Hong, Keyyong
    • Journal of Navigation and Port Research
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    • v.36 no.9
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    • pp.729-735
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    • 2012
  • The primary wave energy conversion by a three-dimensional bottom-mounted oscillating water column (OWC) wave power device in regular waves has been studied. The linear potential boundary value problem has been solved following the boundary matching method. The optimum shape parameters such as the chamber length and the depth of the front skirt of the OWC chamber obtained through two-dimensional numerical tests in the frequency domain have been applied in the design of the present OWC chamber. Time-mean wave power converted by the OWC device and the time-mean second-order wave forces on the OWC chamber structure have been presented for different wave incidence angles in the frequency-domain. It has been shown that the peak period of $P_m$ for the optimum damping parameter coincides with the peak period of the time.mean wave drift force when ${\gamma}=0$.

Effects on Nonlinear Ship Motions on Ship Maneuvering in Large Amplitude Waves (비선형 선박운동을 고려한 대파고 파랑 중 조종성능에 대한 연구)

  • Seo, Min-Guk;Kim, Yong-Hwan;Kim, Kyong-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.6
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    • pp.516-527
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    • 2011
  • This paper considers a numerical analysis of ship maneuvering performance in the high amplitude incident waves by adopting linear and nonlinear ship motion analysis. A time-domain ship motion program is developed to solve the wave-body interaction problem with the ship slip speed and rotation, and it is coupled with a modular type 4-DOF maneuvering problem. Nonlinear Froude-Krylov and restoring forces are included to consider weakly nonlinear ship motion. The developed method is applied to observe the nonlinear ship motion and planar trajectories in maneuvering test in the presence of incident waves. The comparisons are made for S-175 containership with existing experimental data. The nonlinear computation results show a fair agreement of overall tendency in maneuvering performance. In addition, maneuvering performances with respect to wave slope is predicted and reasonable results are observed.