투수층 매설에 의한 해빈안정화에 관한 연구

허동수(Hur Dong-Soo),이우동(Lee Woo-Dong),전호성(Jeon Ho-Sung) 대한토목학회 2010 대한토목학회논문집 B Vol.30 No.3B

본 연구에서는 투수층 매설에 따른 해빈안정화의 효과를 논의하기 위하여, 파 · 투과성구조물 · 해빈/해저지반의 상호간섭을 직접해석 할 수 있는 3D-수치모델(LES-WASS-3D; 허동수와 이우동, 2007)을 이용하였다. 이 모델은 투과성구조물 내부의 유체저항으로서 층류저항, 난류저항, 관성저항을 포함하고 있으며 격자 크기보다 작은 와류를 고려하기 위하여 LES기법을 도입하고 있다. 먼저, 기존의 수리모형 실험치와 본 연구의 계산치를 비교 · 검토하여 이용한 수치모델의 타당성 및 유효성을 검증한 후, 해빈 내부에 투수층을 설치하여 수치시뮬레이션을 실시하였다. 수치실험결과를 통하여 투수층 매설에 따른 평균지하수위의 하강, 이안류 강도의 저하 등, 배수의 메커니즘을 파악한 후, 투수층의 배치형태(평균입경, 두께, 매설깊이, 경사) 및 입사파조건(파고, 주기)에 따른 해빈 내부의 평균지하수위분포에 대하여 고찰하였다. The aim of this study is to survey the effects of laying drainage layer in sandy beach on beach stabilization. At first, the numerical model developed by Hur and Lee (2007), which is able to consider the flow through a porous medium with inertia, laminar and turbulent resistance terms, i.e. simulate directly WAve · Structure · Seabed/Sandy beach interaction and can determine the eddy viscosity with LES turbulent model in 3-D wave field (LES-WASS-3D), is validated by comparing with existing experimental data. And then, numerical simulation is carried out to examine the characteristics of wave-sandy beach interaction for a beach with/without drainage layer. From the numerical results, it is shown that mean ground-water level around a foreshore decreases and offshore-ward flow over a seabed reduces in case of a beach with drainage layer. Moreover, the effects of cross profile of drainage layer and incident wave condition on mean ground-water level around a foreshore are also discussed as well the distribution of wave setup around the foreshore.

방류 흐름제어를 위한 투과성 잠제의 적용성 분석

허동수,이우동,Hur, Dong-Soo,Lee, Woo-Dong 한국수자원학회 2016 한국수자원학회논문집 Vol.49 No.1

본 연구에서는 투과성 잠제의 형상 및 평면배치에 따른 방류 흐름제어 기능을 분석하기 위하여 유체 투과성 구조물 해저지반의 비선형 상호간섭을 직접해석 할 수 있는 PBM (Porous Body Model) 기반의 3차원 수치파동수조(NWT; numerical water tank) LES-WASS-3D를 이용하였다. 먼저 이용하는 LES-WASS-3D의 타당성 및 유효성을 확보하기 위하여 투과성 구조물를 통과하는 댐 붕괴파의 전파특성에 관한 수리모형실험과 계산결과를 비교 분석하였다. 투과성 잠제를 고려한 방류시뮬레이션으로부터 투과성 잠제의 적절한 형상 및 평면배치는 방류유속을 저감하고 흐름을 유도하는 데 상당히 효과적인 것을 알 수 있었다. 또한 투과성 잠제의 형상 및 평면배치에 따른 흐름제어에 대한 적용성은 평균류분포, 연직유속분포를 통하여 확인할 수 있었다. The purpose of this study is to examine the control function of discharged flow due to the shape and plane arrangement of permeable submerged breakwater. For the discussion on it in detail, 3-dimensional numerical model based on PBM (Porous Body Model), which is able to simulate directly interaction of Fluid Permeable structure Seabed has been used to simulate water discharge in a NWT (Numerical Water Tank). To verify the applicability, LES-WASS-3D is analyzed comparing to the experimental result about propagation characteristics of dam-break wave through a permeable structure. Using the results obtained from numerical simulation, the effects of the shape and plane arrangement of submerged breakwater on reducing velocity and flow induction have been discussed related to the mean flow distribution and vertical distributions of horizontal velocities around ones.

투과성 잠제의 파랑변형 수치모의를 위한 2D기법과 3D기법의 비교

허동수(Hur Dong Soo),최동석(Choi Dong Seck),이우동(Lee Woo dong) 대한토목학회 2007 대한토목학회 학술대회 Vol.2007 No.10

지진해일의 발생과 전파에 관한 3차원 수치해석기법(LES-WASS-3D)의 적용성 검토

허동수(Dong-Soo Hur),김강민(Kang-Min Kim) 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

파ㆍ수중방파제ㆍ지반의 비선형 동적응답에 관한 연구

허동수(DONG-SOO HUR),김창훈(CHANG-HOON KIM),염경선(GYEONG-SEON YEOM),김도삼(DO-SAM KIM) 한국해양공학회 2005 韓國海洋工學會誌 Vol.19 No.6

Recently, various-shaped coastal structures have been studied and developed. Among them, the submerged breakwater became generally known as a more effective structure than other structures, because it not only serves its original function, but also has the ability to preserve the coastal environment. Most previous investigations have been focused on the wave deformation and energy dissipation due to submerged breakwater, but less interest was given to their internal properties and dynamic behavior of the seabed foundation under wave loadings. In this study, a direct numerical simulation (DNS) is newly proposed to study the dynamic interaction between a permeable submerged breakwater over a sand seabed and nonlinear waves, including wave breaking. The accuracy of the model is checked by comparing the numerical solution with the existing experimental data related to waveㆍpermeable submerged breakwaterㆍseabed interaction, and showed fairly nice agreement between them. From the numerical results, based on the newly proposed numerical model, the properties of the wave-induced pore water pressure and the flow in the seabed foundation are studied. In relation to their internal properties, the stability of the permeable submerged breakwater is discussed.

파·구조물·지반의 비선형 동적응답해석을 위한 직접수치해석기법의 개발

허동수(Hur, Dong Soo),김창훈(Kim, Chang Hoon),이광호(Lee, Kwang Ho),김도삼(Kim, Do Sam) 한국해안해양공학회 2005 한국해안해양공학회 논문집 Vol.17 No.2

파랑하중하의 지반내 간극수압의 정확한 평가는 연안구조물에서 지반의 안정성을 검토하는데 중요한 요소이다. 파·구조물 지반의 상호간섭에 대한 대부분의 기존 수치모델은 파동장과 지반부를 분리하여 해석하는 Hybrid기법을 적용하고 있기 때문에, 보다 고정도로 이들의 상호간섭을 모의하기 위해서는 파랑하중하에서 파·구조물·지반을 일체화한 수치모델의 개발이 필요하다. 본 연구에서는 투과층의 다양한 기하학적인 형태에 따라 층류저항까지 고려한 모델화 된 유체저항을 도입하여 파 구조물 지반의 비선형동적응답을 해석하기 위한 직접수치해석기법을 새롭게 제안하였다 직접수치해석기법은 Hybrid기법과는 달리 유체와 다공질매체의 접합면에서 특별한 경계조건을 필요로 하지 않는다. 파·구조물·지반의 상호간섭에 대해 기존의 수리실험결과와 본 연구의 계산결과를 비교함으로써 좋은 일치성을 확인할 수 있었다. 따라서 새롭게 제안된 본 수치기법은 파 구조물 지반의 비선형동적응답을 평가하는 유용한 기법으로 판단된다. Accurate estimation of the wave-induced pore water pressure in the seabed is key factor in studying the stability of the seabed in the vicinity of coastal structure. Most of the existing numerical models for wave structure seabed interaction have been linked through applying hybrid numerical technique which is analysis method separating the wave field and seabed regime. Therefore, it is necessary to develope a numerical model f3r simulating accurately wave·structure· seabed interaction under wave loadings by the single domain approach for wave field and seabed regime together. In this study, direct numerical simulation is newly proposed. In this model, modeled fluid drag has been used to detect the hydraulic properties according to the varied geometrical shape inside the porous media by considering the turbulence resistance as well as laminar resistance. Contrary to hybrid numerical technique, direct numerical simulation avoids the explicit formulation of the boundary conditions at the fluid/porous media interface. A good agreement has been obtained by the comparison between existed experimental results by hydraulic model test and direct numerical simulation results far wave ·structure·seabed interaction. Therefore, the newly proposed numerical model is a powerful tool for estimating the nonlinear dynamic responses among a structure, its seabed foundation and water waves.

지진해일(고립파) 발생시 투수층 매설에 따른 연안에서의 처오름 변화에 관하여

허동수(Dong Soo Hur),구남헌(Nam Hean Goo),박종배(Jong Bae Park),안성욱(Sung Wook An) 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

파랑-구조물-지반 상호작용에 의한 혼성제 주변 해저지반의 3차원 동적응답 특성

허동수(Dong-Soo Hur),박종률(Jong-Ryul Park),이우동(Woo-Dong Lee) 한국해양공학회 2016 韓國海洋工學會誌 Vol.30 No.6

If the seabed is exposed to high waves for a long period, the pore water pressure may be excessive, making the seabed subject to liquefaction. As the water pressure change due to wave action is transmitted to the pore water pressure of the seabed, a phase difference will occur because of the fluid resistance from water permeability. Thus, the effective stress of the seabed will be decreased. If a composite breakwater or other structure with large wave reflection is installed over the seabed, a partial standing wave field is formed, and thus larger wave loading is directly transmitted to the seabed, which considerably influences its stability. To analyze the 3-D dynamic response characteristics of the seabed around a composite breakwater, this study performed a numerical simulation by applying LES-WASS-3D to directly analyze the wave-structure-soil interaction. First, the waveform around the composite breakwater and the pore water pressure in the seabed and rubble mound were compared and verified using the results of existing experiments. In addition, the characteristics of the wave field were analyzed around the composite breakwater, where there was an opening under different incident wave conditions. To analyze the effect of the changed wave field on the 3-D dynamic response of the seabed, the correlation between the wave height distribution and pore water pressure distribution of the seabed was investigated. Finally, the numerical results for the perpendicular phase difference of the pore water pressure were aggregated to understand the characteristics of the 3-D dynamic response of the seabed around the composite breakwater in relation to the water-structure-soil interaction.

조위차 극복을 위한 잠제 및 부유식 방파제 혼합형에 대하여

허동수(Hur, Dong Soo),이상엽(Lee, Sang Yeob),이우동(Lee, Woo Dong),정연명(Jeong, Yeon Myeong) 대한토목학회 2016 대한토목학회 학술대회 Vol.2016 No.10

잠제가 설치 된 부산 송도해수욕장의 해빈류 예측에 관한 3차원 수치해석기법(LES-WASS-3D)의 적용

허동수(Dong-Soo Hur),이우동(Woo-Dong Lee),김명규(Myoung-Kyu Kim),윤종성(Jong-Sung Yoon) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.4

This study examined the field application of a 3?D numerical model (LES?WASS?3D) to the estimation of the nearshore current at Songdo beach, Busan. The wave and tide conditions observed at Songdo beach during Typhoon Ewiniar (July 10, 2006) were used in a numerical simulation. The numerical wave heights were in good agreement with the field data. The spatial distributions of the wave heights, mean water levels, and mean flows obtained from the numerical simulation are discussed in relation to the bottom topographical change near Songdo beach before and after Typhoon Ewiniar. The results revealed that LES?WASS?3D is a powerful tool for estimating the nearshore current in the field.