• 제목/요약/키워드: 비특이화 간접 경계적분방정식 방법

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비특이화 간접경계적분방정식 방법을 이용한 부유식 구조물의 유체동역학적 거동에 대한 주파수영역 해석 (Frequency Domain Analysis for Hydrodynamic Responses of Floating Structure using Desingularized Indirect Boundary Integral Equation Method)

  • 오승훈;정동호;조석규;남보우;성홍근
    • 대한조선학회논문집
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    • 제56권1호
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    • pp.11-22
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    • 2019
  • In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.

비특이화 간접경계적분방정식방법을 이용한 2차원 수치수조 개발 및 적용 (Development and Application of Two-Dimensional Numerical Tank using Desingularized Indirect Boundary Integral Equation Method)

  • 오승훈;조석규;정동호;성홍근
    • 한국해양공학회지
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    • 제32권6호
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    • pp.447-457
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    • 2018
  • In this study, a two-dimensional fully nonlinear transient wave numerical tank was developed using a desingularized indirect boundary integral equation method. The desingularized indirect boundary integral equation method is simpler and faster than the conventional boundary element method because special treatment is not required to compute the boundary integral. Numerical simulations were carried out in the time domain using the fourth order Runge-Kutta method. A mixed Eulerian-Lagrangian approach was adapted to reconstruct the free surface at each time step. A numerical damping zone was used to minimize the reflective wave in the downstream region. The interpolating method of a Gaussian radial basis function-type artificial neural network was used to calculate the gradient of the free surface elevation without element connectivity. The desingularized indirect boundary integral equation using an isolated point source and radial basis function has no need for information about the element connectivity and is a meshless method that is numerically more flexible. In order to validate the accuracy of the numerical wave tank based on the desingularized indirect boundary integral equation method and meshless technique, several numerical simulations were carried out. First, a comparison with numerical results according to the type of desingularized source was carried out and confirmed that continuous line sources can be replaced by simply isolated sources. In addition, a propagation simulation of a $2^{nd}$-order Stokes wave was carried out and compared with an analytical solution. Finally, simulations of propagating waves in shallow water and propagating waves over a submerged bar were also carried and compared with published data.