혼성방파제의 케이슨에 작용하는 파압과 선단 주변에서 파랑특성에 관한 3차원수치시뮬레이션 = 3D-Numerical Simulation of Wave Pressure Acting on Caisson and Wave Characteristics near Tip of Composite Breakwater

다국어 초록 (Multilingual Abstract)

It has been widely known that the effect of diffracted waves at the tip of composite breakwater with finite length causes the change of standing wave height along the length of breakwater, the spatial change of wave pressure on caisson, and the occurrence of meandering damage on the different sliding distance in sequence. It is hard to deal with the spatial change of wave force on trunk of breakwater through the two-dimensional experiment and/or numerical analysis. In this study, two and three-dimensional numerical techniques with olaFlow model are used to approach the spatial change of wave force including the impulsive breaking wave pressure applied to trunk of breakwater, the effect of rear region, and the occurrence of diffracted waves at the tip of caisson located on the high crested rubble mound. In addition, it is thoroughly studied the mean wave height, mean horizontal velocity, and mean turbulent kinetic energy through the numerical analysis. In conclusion, it is confirmed that the larger wave pressure occurs at the front wall of caisson around the still water level than the original design conditions when it generates the shock-crushing wave pressure checked by not two-dimensional analysis, but three-dimensional analysis through the change of wave pressure applied to the caisson along the length of breakwater.

국문 초록 (Abstract)

유한길이의 혼성방파제 선단에서 발생되는 회절파의 영향으로 방파제 길이를 따라 중복파고가 변동하고, 이로 인하여 케이슨에 작용하는 파압이 공간적으로 변동하며, 또한 케이슨의 활동거리가 상이한 사행피해가 발생한다는 것은 잘 알려져 있다. 제체에 작용파력의 공간적인 변동은 2차원적인 실험이나 수치해석으로서는 접근될 수 없는 문제이다. 본 연구는 olaFlow 모델을 적용하여 고천단의 사석마운드 상에 놓인 케이슨의 선단 주변에서 회절파의발생과 배후역으로의 영향 및 제체에 작용하는 충격쇄파압을 포함한 파압의 공간적인 변동 등을 2차원 및 3차원수치기법으로 접근한다. 또한, 수치해석에서는 혼성방파제 주변에서 평균파고, 평균수평유속 및 평균난류운동에너지의변동특성을 면밀히 분석·검토한다. 이로부터 동일한 입사파랑에 대해 케이슨에 작용하는 파압분포가 방파제의 길이에 따라 크게 변동하며, 2차원수치해석에서는 발생되지 않았든 충격쇄파압이 3차원수치해석에서는 발생되는 경우가나타나고, 충격쇄파압의 발생 시 경우에 따라 기존의 설계조건보다 매우 큰 파압이 정수면 근방의 케이슨 전면 벽체에 작용되는 등의 중요한 결과를 확인할 수 있었다.

참고문헌 (Reference)

• 1 정재상, "회절을 고려한 반무한방파제 형식의 직립구조물에 작용하는 지점별 파력 분포" 한국해안,해양공학회 28 (28): 240-249, 2016
• 2 이광호, "파-흐름 공존장내 잠제 주변에서 OLAFOAM에 의한 파랑특성의 수치해석" 한국해안,해양공학회 28 (28): 332-349, 2016
• 3 김영택, "경사식방파제 제두부에 거치된 Tetrapod의 안정중량 및 피복범위에 관한 수리실험: 비쇄파 조건" 한국해안,해양공학회 29 (29): 389-398, 2017
• 4 Sulisz, W., "Wave loads on caisson founded on multilayered rubble base" ASCE 123 (123): 91-101, 1997
• 5 Kondo, S., "Wave dissipating structures" Morikita Publishing Co. Ltd 1983
• 6 Chen, X., "Use of impulses to determine the reaction force of a hydraulic structure with an overhang due to wave impact" 147 : 75-88, 2019
• 7 Higuera, P., "Three-dimensional interaction of waves and porous coastal structures using Open-FOAM. Part I: Formulation and validation" 83 : 243-258, 2014
• 8 Lara, J. L., "Three-dimensional interaction of wave and porous coastal structures : Part II : Experimental validation" 64 : 26-46, 2012
• 9 Ramsden, J. D., "TSUNAMI: Forces on a vertical wall caused by long waves, bores, and surges on a dry bed" California Institute of Technology 1993
• 10 Goda, Y., "Random seas and design of maritime structures" World Scientific Publishing, Co. Ltd 2010
• 11 Burcharth, H.F., "On stationary and nonstationary porous flow in coarse granular materials: European Community, MAST G6-S: Project 1, Wave Action on and in Coastal Structures"
• 12 Mostafa, A. M., "Nonlinear wave, composite breakwater, and seabed dynamic interaction" ASCE 125 (125): 88-97, 1999
• 13 Ito, Y., "Meandering damage of composite type breakwater" Port and Harbour Res. Inst 112-, 1971
• 14 Kim, D. S., "Linear wave pressure distributions and loads acting on the vertical caisson of composite breakwater, and resulting wave reflection and transmission coefficients" 20 (20): 747-754, 2000
• 15 Castellino, M., "Large impulsive forces on recurved parapets under non-breaking waves. A numerical study" 136 : 1-15, 2018
• 16 Higuera, P., "Laboratory-scale swash flows generated by a non-breaking solitary wave on a steep slope" 847 : 186-227, 2018
• 17 Jensen, B., "Investigations on the porous media equations and resistance coefficients for coastal structures" 84 : 56-72, 2014
• 18 Bagnold, R. A., "Interim report on wave pressure research" 12 : 202-226, 1939
• 19 Takahashi, S., "Generation mechanism of impulsive pressure by breaking wave on a vertical wall" 22 : 3-31, 1983
• 20 Takahashi, S., "Experimental study of impulsive pressure on composite breakwaters-Fundamental feature of impulsive pressure and the impulsive pressure coefficient-" 31 (31): 33-72, 1993
• 21 Shimosako, K., "Estimating the sliding distance of composite breakwaters due to wave forces inclusive of impulsive forces" 1580-1594, 1994
• 22 Cuomo. G., "Dynamic response and sliding distance of composite breakwaters under breaking and non-breaking wave attack" 58 : 953-969, 2011
• 23 Tsuda, M., "Design procedures for a caisson wall against impulsive wave forces" 22 : 667-672, 2006
• 24 Morihira, M., "Computing method of sea waves and diffraction diagrams" Port and Harbour Res. Inst 21-, 1965
• 25 Ye, J., "Breaking wave-induced response of composite breakwater and liquefaction in seabed foundation" 85 : 72-86, 2014
• 26 Jeng, D. S., "An integrated model for the wave-induced seabed response around marine structures : Model verifications and applications" 72 : 1-19, 2013
• 27 Takahashi, S., "A proposal of impulsive pressure coefficient for design of composite breakwaters" 489-504, 1994
• 28 Hsu, T. J., "A numerical model for wave motions and turbulence flows in front of a composite breakwater" 46 (46): 25-50, 2002
• 29 Ghosal, S., "A dynamic localization model for large-eddy simulation of turbulent flows" 286 : 229-255, 1995