Measurement and Numerical Model on Wave Interaction with Coastal Structure

해안구조물과 파랑상호작용에 관한 수치모델 및 실험

  • Kim, In-Chul (Division of Architecture and Civil Engineering, Dongseo University)
  • 김인철 (동서대학교 건축.토목공학부)
  • 발행 : 2009.02.28

초록

In recent years, there's been strong demand for coastal structures that have a permeability that serves water affinity and disaster prevention from wave attack. The aim of this study is to examine the wave transformation, including wave run-up that propagates over the coastal structures with a steep slope. A numerical model based on the nonlinear shallow water equation, together with the unsteady nonlinear Darcy law for fluid motion in permeable underlayer and laboratory measurements was carried out in terms of the free surface elevations and fluid particle velocities for the cases of regular and irregular waves over 1:5 impermeable and permeable slopes. The numerical results were used to evaluate the application and limitations of the PBREAK numerical model. The numerical model could predict the cross-shore variation of the wave profile reasonably, but showed less accurate results in the breaking zone that the mass and momentum influx is exchanged the most. Except near the wave crest, the computed depth averaged velocities could represent the measured profile below the trough level fairly well.

최근에 해안구조물의 시공에 있어 친수성 및 방재 기능을 동시에 갖는 구조물이 검토되는 사례가 증가하고 있다. 본 연구의 목적은 비교적 급한 1:5 사면을 가진 해안구조물 위로 전파하는 파랑변형 및 파의 처오름을 예측하는 것이다. 사면 위의 파랑변형 및 처오름을 해석하기 위하여 비선형 천수방정식을 사용하였으며, 투수층 내의 유체운동에는 확장형 Forchheimer의 저항법칙에 근거한 비선형, 비정상 Darcy법칙을 적용하여 규칙파 및 불규칙파를 대상으로 수행되었고, 계산결과는 PBREAK 수치모델의 적용성 및 한계성을 검토하기 위하여 수리모형실험 결과와 비교검토 되었다. PBREAK 수치모델은 사면 위의 파형의 변화를 잘 예측하였으나 질량 및 운동량의 교환이 많이 발생하는 쇄파대 내에서 수리모형실험 결과와 약간의 차이를 보여주었다. 또한 수심평균된 수립자 유속은 파봉 부근을 제외하고 파곡 아래에서 계측한 실험치와 잘 일치하였다.

키워드

참고문헌

  1. 김인철 (2006). 투수성 흐름을 고려한 투수성 구조물의 파랑변형에 관한 수치적 해석, 한국해양공학회지, 20(6), 35-40
  2. 김인철, 정종수 (2000). 투수성 사면에서의 파의 처오름 및 반사에 관한 수치적 해석. 대한토목학회 논문집, 20(5-B), 755-763
  3. Cox, D.T., Kobayashi, N. and Okayasu, A. (1995). Experimental and numerical modeling of surf zone hydrodynamics, Research Report, CACR-95-07, Center for Applied Coastal Research Univ. of Delaware, Newark, Delaware
  4. Goda, (1985). Random seas and design of maritime structure. University of Tokyo Press, Tokyo, Japan
  5. Kobayashi, N., DeSilva G.S. and Watson K.D. (1984). Wave transformation and swash oscillation on gentle and steep slopes, J. Geophys. Research, 94(C1), 951-966 https://doi.org/10.1029/JC094iC01p00951
  6. Kobayashi, N. and Poff, M. T. (1994). Numerical model RBREAK2 for random wave on impermeable coastal structure and beaches. Research Report, CACR-94-12, Center for Applied Coastal Research, University of Delaware, Newark, Delaware
  7. Maden, O. S. and White, S. M. (1976). Energy dissipation on a rough slope. J. Waterways, Harbors and Coastal Engineering Division, ASCE, 102(WWI), 31-48
  8. Nwogu, O. (1993). Alternative from of Boussinesq equations for nearshore wave propagation. J. Waterway, Port, Coast and Ocean Engineering, 119, 618-638 https://doi.org/10.1061/(ASCE)0733-950X(1993)119:6(618)
  9. Raubenheimer, B. (2002). Observation and predictions of fluid velocities in the surfand swash zones, J. Geophy. Research, 107, 11_1-11_4
  10. Raubenheimer, B. and Guza, R.T. (1995). Swash on gently sloping beach, J. Geophysical Research, 100(C5), 8751-8760 https://doi.org/10.1029/95JC00232
  11. Wurjanto, A. and Kobayashi, N. (1991). Numerical model for random waves on impermeable coastal structures and beaches, Research Reoprt, CACR-91-05, Center for Applied Coastal Research, University of Delaware, Newark, Delaware
  12. Wurjanto, A. and Kobayashi, N. (1992). Numerical model for random waves on permeable coastal structures. Research Report, CACR-92-02, Center for Applied Coastal Research, University of Delaware, Newark, Delaware
  13. 出口一郞, 森脇淸 (1996). 透水斜面上への逆上波の解析. 海岸 工學論文集, 일본토목학회, 第43卷, 136-140