• Journal of Korea Water Resources Association
• /
• v.38 no.5 s.154
• /
• pp.355-364
• /
• 2005

In this study, flood inundations have been simulated by using the numerical model FLUMEN solving the shallow-water equations with a finite volume method. Before applying to a real problem, the numerical model is first applied to simplified problems. Obtained numerical results are verified by comparing with available analytical solutions and laboratory measurements. Reasonable agreements are observed. The model is then applied to a simulation of flood events with real geometries. The results of this study will provide basic information to make a flood inundation map.

• Journal of Korea Water Resources Association
• /
• v.37 no.10
• /
• pp.845-855
• /
• 2004

The propagation and associated run-up process of nearshore tsunamis in the vicinity of shorelines have been analyzed by using a two-dimensional numerical model. The governing equations of the model are the nonlinear shallow-water equations. They are discretized explicitly by using a finite volume method and the numerical fluxes are reconstructed with a HLLC approximate Riemann solver and weighted averaged flux method. The model is applied to two problems; The first problem deals with water surface oscillations, while the second one simulates the propagation and subsequent run-up process of nearshore tsunamis. Predicted results have been compared to available analytical solutions and laboratory measurements. A very good agreement has been observed.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.402-407
• /
• 2006

본 연구는 곡선좌표계에서 유한차분기법(finite difference method)을 이용하여 2차원 흐름이 모의가능한 수치모형을 개발하는 것이다. 기존의 연구는 대부분 직교좌표계(cartesian coordinate system)에서의 격자망을 대상으로 개발되고 적용되었기 때문에 불규칙한 흐름의 경계 및 형상을 올바로 표현하기 어려웠다. 유한요소법이나 유한체적법같은 수치모의기법들이 개발되어 비구조격자체계를 구성하고 자연현상에 가까운 경계 표현할 수 있도록 개발되었다. 하지만 위의 기법들은 질량과 운동량과 같은 물리량을 보존하기 위해서 매우 조밀한 격자체계를 가져야만 한다. 이에 본 연구에서는 기존의 문제점들을 해결하기 위하여 곡선좌표계(curvilinear coordinate system)를 이용하여 지배방정식을 표현하고 2차원 흐름을 모의할 수 있는 모형을 구축한다. 수치모형은 leap-frog기법과 1차 정확도의 풍상차분기법(upwind scheme)을 사용하여 구성하였다. 본 연구에서 개발된 모형을 사각수조 및 만곡수로흐름에 적용하여 모의결과를 해석해 및 실험관측값과 비교하였다. 이로부터 본 수치모형이 해석해 및 실측치와 잘 일치하고 있음을 알 수 있었다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.27 no.4
• /
• pp.197-201
• /
• 2015

Experimental and numerical analysis has been carried out in this paper to understand correlation between volume and yield of cellular bulkhead. It was firstly confirmed from these results that the conditions and parameters considered in the finite element analysis were reasonable and realistic due to the fact that the yield loads determined by the two different methods were equivalent in actual. Based on this results, a series of intensive numerical analysis has been further performed and revealed that the yield load varied in direct proportion to the change in the volume of the cellular bulkhead.

• Journal of Korea Water Resources Association
• /
• v.47 no.11
• /
• pp.1061-1066
• /
• 2014

A stable second-order finite volume method was proposed to predict sediment transport under rapidly varied flow conditions such as transcritical flow. For the use under unsteady flow conditions, a sediment transport model was coupled with shallow water equations. HLLC approximate Riemann solver based on a monotone upstream-centered schemes for conservation laws (MUSCL) reconstruction was used for the computation of the flux terms. From the comparisons of dam break flow experiments on erodible beds in one- and two-dimensional channels, good agreements were obtained when proper parameters were provided. Lastly, dam surface erosion problem by overtopped water was simulated. Overall, the numerical solutions showed reasonable results, which demonstrated that the proposed numerical scheme could provide stable and physical results in the cases of subcritical and supercritical flow conditions.

• Journal of Korea Water Resources Association
• /
• v.45 no.11
• /
• pp.1093-1105
• /
• 2012

In this study, the simulations and analyses of flood flow due to a river inundation in a coastal urban area are carried out using a two-dimensional finite volume model with well-balanced HLLC scheme. The target area is a coastal urban area around Gohyun river which is located at Geoje city in Kyungnam province and was extremely damaged due to the heavy rainfall during the period of the typhoon "Maemi" in September 2003. For the purpose of the verification of the numerical model applied in this study, the simulated results are compared and analyzed with the inundation traces. In addition, the flood flow in an urban area is simulated and analyzed according to the scenarios of inflow variation due to the increase and decrease of the intensity of the heavy rainfall, which.

• Journal of Korea Water Resources Association
• /
• v.52 no.11
• /
• pp.887-894
• /
• 2019

We proposed a GPU (Grapic Processing Unit) accelerated kinematic wave model for rainfall runoff simulation and tested the accuracy and speed up performance of the proposed model. The governing equations are the kinematic wave equation for surface flow and the Green-Ampt model for infiltration. The kinematic wave equations were discretized using a finite volume method and CUDA fortran was used to implement the rainfall runoff model. Several numerical tests were conducted. The computed results of the GPU accelerated kinematic wave model were compared with several measured and other numerical results and reasonable agreements were observed from the comparisons. The speed up performance of the GPU accelerated model increased as the number of grids increased, achieving a maximum speed up of approximately 450 times compared to a CPU (Central Processing Unit) version, at least for the tested computing resources.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.6
• /
• pp.79-85
• /
• 2000

본 논문에서는 사질토 지반에 일정기간 계속하여 증가되는 단계별 하중이 작용할 때 발생할수 있는 지반의 밀도화 현상을 hyperbolic model의 매개변수 변화를 고려한 방법으로 유한요소법에 의한 수치적 침하해석에 반영해 주었다. 이를 위해 사질토의 상대밀도별 삼축압축실험을 실시하여 매개변수를 산정하였으며, 이를 토대로 각각의 상대밀도의 변화에 따른 매개변수값을 Lagrange의 다항식 수치보간법으로 프로그램에 반영하였다. 또한 유한요소프로그램 내에서 요소의 체적을 계산하고 체적의 변화를 상대밀도 개념으로 접근함으로서 지반의 밀도화를 프로그램내에서 모사할수 있도록 하였다. 본 연구에서 개발한 해석 프로그램에 의한 지반의 밀도화현상의 모사 결과를 실내 모형기초재하실험에 의하여 비교 분석해 본 결과 기존의 해석 보다 향상된 결과를 나타냄을 알 수 있었다.

• Journal of Korea Water Resources Association
• /
• v.51 no.10
• /
• pp.853-862
• /
• 2018

An adaptive cut-cell grid based 2D inundation analysis model, K-Flood, is developed in this study. Cut cell grid method divides a grid into a flow area and a non-flow area depending the characteristics of the flows. With adaptive mesh refinement technique cut cell method can represent complex flow area using relatively small number of cells. In recent years, the urban inundation modeling using high resolution and fine quality data is increasing to achieve more accurate flood analysis or flood forecasting. K-Flood has potential to simulate such complex urban inundation using efficient grid generation technique. A finite volume numerical scheme of second order accuracy for space and time was applied. For verification of K-Flood, 1) shockwave reflex simulation by circular cylinder, 2) urban flood experiment simulation, 3) Malpasset dam collapse simulation are performed and the results are compared with observed data and previous simulation results.

• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.236-240
• /
• 2017

다양한 분야에서 복합재료의 중요성이 강조되면서 각각의 재료 특성에 따른 물성을 미시역학적으로 구하는 것에 대한 다양한 방법이 제시되고 있다. 본 논문에서는 5개의 혼합 법칙을 선정하여 전산구조해석을 통한 유한요소해석을 비교 검증한다. 그 과정에서 산출된 결과를 통하여 복합재료의 탄성거동의 오차가 1% 미만인 것을 확인하였고, 프로그램의 해석이 적절하다는 것을 검증하였다. 또한 프로그램과 가장 유사한 혼합 법칙이 무엇인지 확인하고, 체적 비에 따른 오차를 비교하여 가장 적합한 체적 비를 선정하였다.