• Title/Summary/Keyword: High-Order Spectral/Boundary-Element Method

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Development of Three-Dimensional Numerical Wave Tank by Using the High-Order Spectral/Boundary-Element Method -Waves Generated by a Uniformly Translating Surface Pressure (고차 스펙트럴/경계요소법을 이용한 3차원 수치 파수조의 개발-균일속도로 전진하는 표면압력에 의한 조파현상-)

  • Kim, Young-Jig;Lee, Young-Woo;Hong, Ji-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.13 no.1 s.31
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    • pp.113-120
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    • 1999
  • In this paper, mathematical formulation of the high-order spectral/boundary-element method is shown. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated in time-domain. Three-dimensional waves generated by a uniformly translating suriace pressure are calculated and discussed. The obtained results are compared with others results, The comparisons show good agreements.

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Numerical Simulation of Incipient Breaking Waves (초기 쇄파의 수치모사)

  • 김용직;김선기
    • Journal of the Society of Naval Architects of Korea
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    • v.39 no.4
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    • pp.1-10
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    • 2002
  • For the time-domain simulation of incipient breaking waves, usually the boundary integral method has been used so far, and it seems to be successful except a problem of too much computation time. The present paper shows a new computation technique for the simulation of breaking wave experiment. This technique uses the high-order spectral/boundary element method and the boundary integral method in sequence, and reduces the computation time remarkably. The wave generation and energy focusing process is efficiently simulated by the high-order spectral/boundary element method. Only the wave over-turning process is simulated by the boundary integral method. In the example calculation result, salient features of breaking waves such as high particle velocities and accelerations are shown.

Numerical Calculation of the free-Surface Flows around a Submerged Body (잠수체 주위 자유표면 유동의 수치계산)

  • 김용직;하영록;홍사영
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.2
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    • pp.11-20
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    • 2003
  • In this paper, the high-order spectral/boundary-element method is developed to calculate the 3-dimensional water waves generated by a submerged body. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated Tn time-domain. Three-dimensional free-surface flows generated by a submerged sphere which is moving under the free-surface are calculated. Through example calculations, nonlinear effects on free-surface profiles and hydrodynamic forces are shown. Comparisons with others' results show good agreements.

Time-Domain Analysis of Nonlinear Wave-Making Phenomena by a Submerged Sphere Oscillating with Large Amplitude (대진폭 조화 운동을 하는 잠수구에 의한 비선형 조파현상의 시간영역 해석)

  • Kim, Yong-Jig;Ha, Young-Rok
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.382-385
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    • 2006
  • A high-order spectral/boundary-element method is newly adapted as an efficient numerical tool. In this method, the velocity potential is expressed as the sum of surface potential and body potential. Then, surface potential is solved fly using the high-order spectral method and body potential is solved fly using the high-order boundary element method. Through the combination of these two methods, the wave-making problems fly a submerged sphere moving with the large amplitude oscillation are solved in time-domain. With the example calculations, nonlinear effects on free-surface profiles and hydrodynamic forces are shown and discussed.

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A Study of Numerical Method for Analysis of the 3-Dimensional Nonlinear Wave-Making Problems (3차원 비선형 조파문제 해석을 위한 수치해법 연구)

  • Ha, Y.R.;An, N.H.
    • Journal of Power System Engineering
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    • v.16 no.5
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    • pp.40-46
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    • 2012
  • For free surface flow problem, a high-order spectral/boundary element method is adapted as an efficient numerical tool. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time domain. In this method, the velocity potential is expressed as the sum of surface potential and body potential. Then, surface potential is solved by using the high-order spectral method and body potential is solved by using the high-order boundary element method. Using the combination of these two methods, the free surface flow problems of a submerged moving body are solved in time domain. In the present study, lifting surface theory is added to the former work to include effects of lift force. Therefore, a new formulation for the basic mathematical theory is introduced to contain the lift body in calculation.

Time Domain Analysis of Nonlinear Wave-Making Problems by a Submerged Sphere Oscillating with Forward Speed (전진 동요하는 잠수구에 의한 비선형 조파문제의 시간영역 해석)

  • Ha, Y.R.;Bae, S.Y.
    • Journal of Power System Engineering
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    • v.14 no.6
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    • pp.75-82
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    • 2010
  • In this study, the topics for free-surface wave simulation, nonlinear hydrodynamic force, and the critical resonance frequency of so-called ${\tau}=U{\omega}/g$=1/4 are discussed. A high-order spectral/boundary element method is newly adapted as an efficient numerical tool. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time domain. In this method, the velocity potential is expressed as the sum of surface potential and body potential. Then, surface potential is solved by using the high-order spectral method and body potential is solved by using the high-order boundary element method. By the combination of these two methods, the wave-making problems by a submerged sphere oscillating with forward speed under the free-surface are solved in time domain.

A Study of Numerical Wave Tank for 3-Dimensional Free Surface Wave Simulation (3차원 자유표면파 모사를 위한 수치 파수조에 관한 연구)

  • Ha, Y.R.;Kim, Y.J.
    • Journal of Power System Engineering
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    • v.15 no.6
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    • pp.27-34
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    • 2011
  • The increasing capabilities of the computers enable us to utilize various numerical schemes for the time-domain simulations concerned with 3-dimensional free-surface wave problems. There are still difficulties to solve such kind of problems, however. That's because long time simulations with large computational domain are needed in time-domain analysis. So, we need faster and more efficient numerical schemes to get the solutions practically for these problems. In this paper, a high-order spectral/boundary-element method is used for the numerical investigation of physics involved in wave-body interaction. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time-domain. To get the robust study in these topics, various numerical tests are performed and compared with others' works.

Time-Domain Analysis of Nonlinear Wave-Making Problems by a Submerged Sphere Oscillating with Large Amplitude (대진폭 조화 운동을 하는 잠수구에 의한 비선형 조파문제의 시간영역 해석)

  • Kim, Yong-Jig;Ha, Young-Rok
    • Journal of Ocean Engineering and Technology
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    • v.20 no.6 s.73
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    • pp.67-74
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    • 2006
  • A high-order spectral/boundary-element method is newly adapted as an efficient numerical tool. This method is one of the most efficient numerical methods by which the nonlinear gravity waves can be simulated and hydrodynamic forces also can be calculated in time-domain. In this method, the velocity potential is expressed as the sum of surface potential and body potential. Then, surface potential is solved by using the high-order spectral method and body potential is solved by using the high-order boundary element method. By the combination of these two methods, the wave-making problems by a submerged sphere oscillating with large amplitude under the free~surface are solved in time-domain. Through the example calculations, nonlinear effects on free-surface profiles and hydrodynamic forces are shown and discussed.