• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.185-186
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• 2022

In this study, a numerical analysis was conducted using a two-dimensional diffusion-wave analysis model to analyze the validity about the application of eco-friendly prefabricated rainwater detention system in grit chamber and permanent pond. As a result of the analysis, it is confirmed that the flood prevention effect, such as a decrease in peak flow rate and a delay in peak time, is excellent, so it is considered reasonable to apply eco-friendly prefabricated rainwater detention system in grit chamber and permanent pond.

• 한국지리정보학회지
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• 제12권3호
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• pp.88-100
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• 2009

본 연구에서는 GIS와 연계한 2차원 확산파 침수해석 모형을 개발하여 2002년 8월 집중호우로 인하여 침수피해가 발생했던 낙동강의 지류인 화포천유역에 대하여 하천제방의 월류 및 붕괴에 따른 침수해석을 실시하였다. 당시의 침수흔적도 및 FLUMEN 모형의 침수해석 결과와 시간별 침수심 및 최대 침수면적의 비교를 통해 모형의 적용성을 평가해 보았다. 침수흔적도와의 비교를 통해 침수면적에 대한 적합도를 분석한 결과 88.61%의 적합도를 갖는 것으로 확인되었으며, FLUMEN 모형과의 비교를 통하여 최대 침수면적 및 침수지역의 공간적 분포가 상당부분 일치하는 것으로 확인되었다. 따라서 2차원 확산파 침수해석 모형의 적용으로 계산된 시간별 침수구역 및 최대 침수면적 등은 홍수에 대비한 위험지역의 파악 및 재난저감 대책을 수립하기 위한 판단자료로 활용될 수 있을 것으로 기대된다.

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.69-78
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• 2004

This paper treats the conditions for the existence of rotating wave solutions of a system modelling the behavior of students in graduate programs at neighbouring universities near each other which is a modified form of the model proposed by Scheurle and Seydel. We assume that both types of individuals are continuously distributed throughout a bounded two-dimension spatial domain of two types (circle and annulus), across whose boundaries there is no migration, and which simultaneously undergo simple (Fickian) diffusion. We will show that at a critical value of a system-parameter bifurcation takes place: a rotating wave solution arises.

• 한국전산유체공학회지
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• 제19권1호
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• pp.15-20
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• 2014

Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code, termed SNUFOAM, which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley model ship. In results, the band width of the volume fraction contours between 0.1 to 0.9 at the hull surface was narrowed by considering the anti-diffusion term.

• 반도체디스플레이기술학회지
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• 제10권3호
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• pp.29-33
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• 2011

Film growth rate and composition variation are numerically analyzed during the selective area growth of InGaN on the GaN triangular stripe microfacet in this study. Both the vapor phase diffusion and the surface diffusion are considered to determine the In composition on the InGaN surface. To obtain the In composition on the surface, flux of In atoms due to the surface diffusion is added to the concentration determined from the Laplace equation which is governing the gas phase diffusion. The solution model is validated by comparing the growth rates from the analyses to the experimental results of GaN and InN films. The In composition and resulting wave length are increased when the surface diffusion is considered. The In content is also increased according to the increasing mask width. The effect of mask width to the In content and wave length is increasing in the case of a small open region.

• 방사선산업학회지
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• 제5권1호
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• pp.87-93
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• 2011

A laboratory experiment using a radioisotope was performed to analyze the characteristics of transport and diffusion of a pollutant released from industrial plants. A wave hydraulic model based on the similarity theory was constructed and used to reappear the tidal wave in the laboratory. Two-dimensional numerical models were used to reproduce the results of a wave hydraulic model. The measured and calculated concentrations were compared with the same conditions. As a result of the comparative study, the time of maximum concentration showed slight difference between them, but the values of maximum concentration were relatively well agreed.

• 한국해안해양공학회지
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• 제5권4호
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• pp.357-368
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• 1993

확산이 지배적인 흐름을 가정하여, 쇄파대의 해향저류와 난류구조에 대한 수치모형이 $ extsc{k}$-$\varepsilon$ 난류모형을 이용하여 개발되었다. 해향저류란 쇄파대에서 바다쪽으로 흐르는 주기평균된 강한 흐름을 말하며 주로 파곡 아래에 나타난다. 롤러에서 쇄파에 의해 발생된 난류는 아래쪽으로 퍼져나가면서 그 기운을 잃게된다. 지배 방정식은 파에 의한 주기평균-전단응력이 고려된 운동 방정식과 쇄파에 의한 난류 에너지 생성이 포함된 $textsc{k}$-와 $\varepsilon$-식으로 구성된다. 이 식들은 삼단계 완전 음해법으로 차분되고, Thomas 알고리즘으로 풀 수 있다. 쇄파지점에 가까운 곳을 제외하면, 모형은 실험값과 좋은 일치를 보여준다

• 소음진동
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• 제10권4호
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• pp.610-614
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• 2000

Cellular Automata(CA)s are used as a simple mathematical model to investigate self-organization in statistical mechanics, which are originally introduced by von Neumann and S. Ulam at the end of the 1940s. CAs provide a framework for a large class of discrete models with homogeneous interactions, which are characterized by the following fundamental properties: 1) CAs are dynamical systems in which space and time are discrete. 2) The systems consist of a regular grid of cells. 3) Each cell is characterized by a state taken from a finite set of states and updated synchronously in discrete time steps according to a local, identical interaction rule. 4) The state of a cell is determined by the previous states of a surrounding neighborhood of cells. A cellular automaton has been attracted wide interest in modeling physical phenomena, which are described generally, partial differential equations such as diffusion and wave propagation. This paper describes one and two-dimensional analysis of wave propagation phenomena modeled by CA, where the local interaction rules were derived referring to the Lattice Gas Model reported by Chen et al., and also including finite difference scheme. Modeling processes by using CA are discussed and the simulation results of wave propagation with one wave source are compared with that by finite difference method.

• 물과 미래
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• 제27권2호
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• pp.73-83
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• 1994

확산현상, 표사유동 및 인간의 여러 활동이 실제 연안해역에서 일어나므로 연안해역 해수운동의 물리적 특성을 파악하고 해석하는 것은 중요한 의미를 지닌다. 본 연구에서는 연안해역에서의 파랑변형과 평균해수위 변동 그리고 연안유속 분포양상에 대해 여러 인자들이 미치는 영향을 2차원 유한차분 모형(ADI, Up-wind)을 이용하여 분석하였다. 계산결과로는 수치모형을 해저경사가 일정한 2차원 지형에 적용하여 해저경사, 입사파고, 파향각, 파주기, 마찰계수 및 수평확산계수가 연안해역 특히 쇄파대내에서 파랑변형, 평균해수위 변동 및 연안유속 분포에 미치는 영향을 분석하였다.

• 물과 미래
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• 제18권3호
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• pp.265-270
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• 1985

The prediction of a design-flood hydrograph at a particular site on a river may be based on the derivation of discharge or stage hydrograph at an upstream section, togeater with a method to route this hydrograph along the rest of river. On the other hand, flood routing methods provide a useful tool for the analysis of flooding in all but the smaller catchment, and these methods are largely stored into hydrological method and hydraulic method. Although the Muskingum Method as a hydrological method ignores dynamic effects on the flood wave, Muskingum-Cunge Method based on hydraulic method is possible to improve the method so that it gives a good approximation to the solution of the linear convective-diffusion equation. This is made on the basis of the finite diffeience equation for the Muskingum Method. In the study, the outflows predicted by Muskingum-Cunge Method are campared with the observed outflows of the Pyung Chang River.