• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.194-194
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• 2017

Flooding is one of the most serious and frequently occurred natural disaster at many regions around the world. Especially, under the climate change impact, it is more and more increasingly trend. To reduce the flood damage, flood forecast and its accuracy analysis are required. This study is conducted to analyze the accuracy of the real-time flood forecasting of a coupled meteo-hydrological model for the Han River basin, South Korea. The LDAPS (Local Data Assimilation and Prediction System) products with the spatial resolution of 1.5km and lead time of 36 hours are extracted and used as inputs for the SURR (Sejong University Rainfall-Runoff) model. Three statistical criteria consisting of CC (Corelation Coefficient), RMSE (Root Mean Square Error) and ME (Model Efficiency) are used to evaluate the performance of this couple. The results are expected that the accuracy of the flood forecasting reduces following the increase of lead time corresponding to the accuracy reduction of LDAPS rainfall. Further study is planed to improve the accuracy of the real-time flood forecasting.

• 설비공학논문집
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• 제16권7호
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• pp.658-666
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• 2004

In this paper, a two-dimensional transient ground-coupled numerical model for slab-on-grade foundation is developed and integrated into EnergyPlus. A validation analysis is first presented to ensure that for the developed building foundation heat transfer module is properly implemented within EnergyPlus. Then, the predictions from the developed model are compared to those obtained from the simplified building foundation model currently used in EnergyPlus. The results show that the developed foundation heat transfer module accounts better for the effects of the ground thermal mass attributed to the ground than the simplified foundation model currently used in EnergyPlus.

• Coupled systems mechanics
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• 제11권1호
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• pp.1-14
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• 2022

The key parameter that affects the consolidation process of soil is the coefficient of permeability. The common assumption in the consolidation analysis is that the coefficient of permeability is porosity-dependent. However, various authors suggest that the strain-dependency of the coefficient of permeability should also be taken into account. In this paper, we present results of experimental and numerical analyses, with an aim to determine the strain-dependency of the coefficient of permeability. We present in detail both the experimental procedure and the finite element formulation of the two-dimensional axisymmetric numerical model of the oedometer test (standard and modified). We perform a set of experimental standard and modified oedometer tests. We use these experimental results to validate our numerical model and to define the model input parameter. Finally, by combining the experimental and numerical results, we propose the expression for the strain-dependent coefficient of permeability.

• 한국지반공학회논문집
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• 제30권9호
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• pp.67-75
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• 2014

방대한 저장량으로 차세대 에너지원으로 평가받는 메탄가스 하이드레이트는 생산과정에서 유발될 수 있는 문제를 최소화하고 최적의 생산조건을 선정하기 위한 하이드레이트 포함한 다공질 재료의 THM 현상에 대한 프로그램의 개발이 절실하다. 기존의 해석 프로그램들은 국제공동연구를 통하여 프로그램들간의 상호 비교검증을 진행하고 있으나, 예측값의 불일치와 수렴성에 문제가 있는 것으로 나타났다. 본 논문에서는 다공질 재료내 메탄 하이드레이트의 해리 현상을 해석할 수 있는 fully coupled THM 유한요소 프로그램을 개발하였다. Methane hydrate, soil, water, 및 methane gas의 질량보존의 법칙, 에너지 보존의 법칙, 그리고 힘평형 방정식으로부터 지배방정식을 유도하였다. 다양한 주변수들의 조합을 통하여 주변수를 변위, 가스 포화도, 유체압, 온도, 하이드레이트 포화도로 선택하였으며, 상변화 전영역에서 해석이 가능하도록 하였다. 하이드레이트의 해리를 예측하는 모델은 kinetic model을 이용하였다. 개발된 THM 유한요소 프로그램을 이용하여 메탄가스 생산에 관한 Masuda의 실내 모형실험 결과와 비교적 분석을 수행하였으며, 해의 수렴성과 안정성을 확인할 수 있었다.

• 한국지반공학회논문집
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• 제23권6호
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• pp.77-84
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• 2007

유입량과 라이닝에 작용하는 간극수압은 터널 설계시 고려해야 할 중요한 요소 중 하나이다. 간극수압의 발생은 누수를 가속화시키며 라이닝 열화를 초래한다. 본 논문에서는 모형실험을 통하여 배수시스템 기능저하로 인한 간극수압의 발생과 그 영향을 조사하였다. 배수시스템 기능저하거동은 배수재의 투수계수제어법과 유량 조절법으로 모사화 하여 터널 라이닝의 잔류수압발생 메카니즘을 확인하였다. 또한, 유량제어법이 배수시스템 기능저하현상을 모사하기에 보다 더 효과적인 방법임을 알 수 있었다. 모형실험을 수치해석으로 재현한 결과, 배수시스템 기능저하로 인한 영향을 Coupled 수치 모델링을 통해 이론적으로 예측 가능함을 확인할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.686-689
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• 2005

A numerical simulation method is developed to analyze the dynamic response of a cantilever switch, which is driven by electrostatic force and a basic component of electro-mechanical coupled system. First, point-charges model on conductor is proposed as a lumped parameter of electrical part. Then, this model is easily incorporated into a multi-body dynamics analysis algorithm, the generalized recursive dynamics formula previously developed by our research group. The resulting motion of a coupled overall system is formulated as a differential algebraic equation form including electrical and mechanical variables together. The equation is simultaneously solved in every time step. To implement this approach into the useful dynamics analysis tool, we used multibody dynamics software (RecurDyn) based on the generalized recursive formula using relative coordinate. The developed numerical simulation tool is evaluated by applying to many different driving condition and switch configuration. The final analysis model will be added to RecurDyn as a basic module for dynamics analysis of electro-mechanical coupled system.

• 전자공학회논문지B
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• 제32B권10호
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• pp.1286-1293
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• 1995

Modified equivalent lumped element model for square spiral inductors have been derived. This model shows more accurate analysis performance than conventional models, and gives reliable design parameters. And this model is made through comparison among distributed multiple coupled line, numerical analysis and experimental data.

• 한국결정성장학회지
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• 제10권2호
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• pp.128-133
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• 2000

Numerical analysis of the transport phenomena in an inductively coupled plasma reactor was conducted with two-dimensional axisymmetric model including the electromagnetic field model, electron and species density models. The spatial distribution of the charged species in the ion flux to the wafer have been calculated to examine the influence of the process conditions including antenna and reactor geometry. The antenna radius had a significant influence on the plasma state and axial ion flux distribution.

• Water Engineering Research
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• 제1권1호
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• pp.25-37
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• 2000

This study presents some results of a preliminary study for the coupled precipitation and river flow prediction system. The model system in based on three numerical models, Mesoscale Atmospheric Simulation model for generating atmospheric variables. Soil-Plant-Snow model for computing interactions within soil-canopy-snow system as well as the energy and water exchange between the atmosphere and underlying surfaces, and TOPMODEL for simulating stream flow, subsurface flow, and water tabled depth in an watershed. The selected study area is the 2,703 $\alpha_4$ $\km_2$ Soyang River basin with outlet at Soyang dam site. In addition to providing the results of rainfall and stream flow predictions, some results of DEM and GIS application are presented. It is obvious that the accurate river flow predictions are highly dependant on the accurate predictation predictions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.525-525
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• 2005

This study is for the seismic analysis and the structural integrity evaluation of the box beam for supporting nuclear fuel-transfer-basket of the HANARO reactor pool. For performing the seismic analysis and evaluating the structural integrity in air or submerged condition, the finite element model of the fuel-transfer-basket and its supporting box beam(the coupled model) was developed. The hydrodynamic effect is also considered by using added mass concept. The seismic response spectrum analyses of the coupled model under the design floor response spectrum loads of Safe Shutdown Earthquake(SSE) were performed. Through the numerical experiments, the analysis results show that the stress values of the coupled model lot the structural integrity are within the ASME Code limits.