Journal of Korean Society of Coastal and Ocean Engineers (한국해안해양공학회지)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Numerical Analysis on the Determination of Hydraulic Characteristics of Rubble Mound Breakwater

경사식 방파제의 수리특성 결정을 위한 수치해석

  • 박현주 (신구대학 토목과) ;
  • 전인식 (건국대학교 토목공학과) ;
  • 이달수 (한국해양연구원 연안·항만공학연구본부)
  • Published : 2002.03.01
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Abstract

A numerical method to efficiently secure necessary design informations of the hydraulic characteristics of rubble mound breakwater was attempted here. The method combines the exterior wave field with the interior wave field which is formulated incorporating porous media flow inside the breakwaters. An approximate method based on the long wave assumption was used for the exterior wave field while a boundary element method was used for the interior wave field. A hydraulic experiment was also performed to verify the validity of the numerical analysis. The numerical results were compared with experimental data and results from existing formulae. They generally agreed in both reflection and transmission coefficients. The calculated pore pressures also showed a similar pattern with experimental data, even if they gave some significant differences in their values fur some cases. The main cause of such differences can be attributed to the strongly nonlinear wave field occurring on the frontal slope of the breakwater. The direct input of dynamic pressures(measured from hydraulic experiment) into the numerical method was suggested as a promising method to enhance the predictability of pore pressures.

경사식 방파제의 설계에 필요한 정보를 제공할 목적으로 수리특성들의 계산을 비교적 쉽게 수행하기 위한 수치해석기법의 수립을 시도하였다. 수치해석은 방파제 외부의 파동장과 내부 공극매체에서의 파동장을 결합시킴으로써 반사율, 전달율(월파전달율과 투과전달율) 그리고 개체내부의 간극수압을 계산하는 것이다. 외부 파동장은 장파가정의 근사 이론을, 내부 파동장은 경계요소법을 이용하여 해석하였다. 수치해석결과를 수리실험결과와 비교한 결과, 반사율과 전달율은 허용오차 범위내에서 비교적 잘 일치하는 것으로 나타났다. 또한, 간극수압은 정량적으로는 다소의 차이를 보이나 정성적으로는 대체적으로 유사한 성향을 보이는 것으로 나타났다. 정량적 차이를 극복하기 위하여 전사면에서의 비선형 파동장에 의한 동수압을 직접 계측하여 수치해석에 입력하는 방안을 제시하였다

Keywords

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