• Title/Summary/Keyword: 불규칙 파랑

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Numerical Simulation of Monochromatic Wave Propagation Considering Breaking-Induced Currents over Submerged Shoal (쇄파 유도류를 고려한 수중천퇴상 규칙파 전파 수치모의)

  • 윤성범;박준영;정인길;홍경욱
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2002.08a
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    • pp.56-61
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    • 2002
  • 파의 굴절ㆍ회절은 포물형 근사식을 이용하여 상당히 높은 정도의 계산이 가능하다. 이 포물형 근사식은 규칙파 뿐만 아니라 불규칙파에도 적용할 수 있으며, 적당한 에너지 감쇠모형을 추가하면 쇄파까지도 고려할 수 있다. (중략)

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Comparison of Numerical Solutions by TVD Schemes in Simulations of Irregular Waves Propagating over a Submerged Shoal Using FUNWAVE-TVD Numerical Model (FUNWAVE-TVD 수치모형을 이용한 수중천퇴를 통과하는 불규칙파의 수치모의에서 TVD 기법들에 의한 수치해 비교)

  • Choi, Young-Kwang;Seo, Seung-Nam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.30 no.4
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    • pp.143-152
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    • 2018
  • Numerical convergence and stability of TVD schemes have been applied in the FUNWAVE-TVD model were compared. The fourth order accurate MUSCL-TVD scheme using minmod limiter suggested by Yamamoto and Daiguji (1993), the fourth order accurate MUSCL-TVD scheme using van-Leer limiter suggested by Erduran et al. (2005) and the second order accurate MUSCL-TVD scheme using van-Leer limiter in Zhou et al. (2001) were compared. Comparisons of the numerical scheme were conducted with experimental data of Vincent and Briggs irregular wave experiments. In comparison with the fourth order accurate scheme using van-Leer limiter, the fourth order accurate scheme using minmod limiter is less dissipative but required lower CFL condition for stable numerical solution. On the other hand, the scheme using van-Leer limiter required smaller resolution spatial grid due to numerical dissipation, but relatively higher CFL condition can be used compared to the scheme using minmod limiter. In the breaking wave experiments which were conducted using high resolution spatial grid to reduce numerical dissipation, the characteristic of the schemes can be clearly observed. Numerical instabilities and blow-up of the numerical solutions were found in the irregular wave breaking simulation with the scheme using minmod limiter. However, the simulation can be completed with the scheme using van-Leer limiter, but required low CFL condition. Good agreements with the observed data were also observed in the results using van-Leer limiter.

Prediction of Wave Force on a Long Structure of Semi-infinite Breakwater Type Considering Diffraction (회절을 고려한 반무한방파제 형식의 장대구조물에 작용하는 파력 예측)

  • Jung, Jae-Sang;Lee, Changhoon;Cho, Yong-Sik
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.6
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    • pp.424-433
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    • 2015
  • In this study, the wave force distribution acting on a semi-infinite and vertical-type long structure is investigated considering diffraction. An analytical solution of the wave force acting on long structures is also suggested in this study. The wave forces on long structures are evaluated for monochromatic, uni-directional random, and multi-directional random waves. Diffraction effects in front of the breakwater and on the lee side of the breakwater are considered. The wave force on a long structure becomes zero when the relative length of the breakwater (1/L) is zero. The diffraction effects are relatively strong when the relative length of the breakwater is less than 1.0, and the wave forces decrease greatly for long structure when the relative length of the breakwater is larger than 0.5. Therefore, it is necessary to consider diffraction effects when the relative length of the breakwater is less than 1.0, and the relative length of the breakwater must be at least 0.5 in order to obtain a reduction of wave force on long structures.

Theoretical analysis of the lightwave localization phenomenon on the random transmission line (part 2) : simulation (랜덤 선로상의 광 국재현상에 관한 해석(2) : 시뮬레이션)

  • 최영규
    • Korean Journal of Optics and Photonics
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    • v.14 no.4
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    • pp.434-442
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    • 2003
  • Taking advantage of the probability function, we have analyzed the localization phenomenon of the solution of a propagating function under the condition that the propagation constants are randomly distributed. For example, we have investigated the localization phenomenon of the voltage wave for a transmission line in which the characteristic impedance is randomly distributed. We have confirmed that the localized solution is in existence on the random lossless transmission line. Even in the case that the voltage wave is impulsively excited by the current source, the voltage wave is localized. Because the light wave is seriously affected at the localized position in the lossy transmission line, we have determined that the light wave localization phenomena are generated by multi-reflection.