• Structural Engineering and Mechanics
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• 제60권5호
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• pp.809-828
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• 2016

In deep open pit mines, slope stability is very important. Particularly, increasing the depths increase the risks in mines having weak rock mass. Blasting operations in this type of open pits may have a negative impact on slope stability. Several or combination of methods can be used in order to enable better analysis in this type of deep open-pit mines. Numerical modeling is one of these options. Many complex problems can be integrated into numerical methods at the same time and analysis, solutions can be performed on a single model. Rock failure criterions and rock models are used in numerical modeling. Hoek-Brown and Mohr-Coulomb terms are the two most commonly used rock failure conditions. In this study, mine planning and discontinuity conditions of a lignite mine facing two big landslides previously, has been investigated. Moreover, the presence of some damage before starting the study was identified in surrounding structures. The primary research of this study is on slope study. In slope stability analysis, numerical modeling methods with Hoek-Brown and Mohr-Coulomb failure criterions were used separately. Preparing the input data to the numerical model, the outcomes of patented-blast vibration minimization method, developed by co-author was used. The analysis showed that, the model prepared by applying Hoek-Brown failure criterion, failed in the stage of 10. However, the model prepared by using Mohr-Coulomb failure criterion did not fail even in the stage 17. Examining the full research field, there has been ongoing production in this mine without any failure and damage to surface structures.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.245-245
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• 2015

In the recent years, due to long-lasting heavy rainfall events, a large number of landslides have been observed in the mountainous area of the world. Such landslides can also form a dam as it blocks the course of a river, which may burst and cause a catastrophic flood. Numerical analysis of landslide dam formation is rarely available, while laboratory experimental studies often use assumed shape to analyze the landslide dam failure and flood hydraulics in downstream. In this study, both experimental and numerical studies have been carried out to investigate the formation of landslide dam. Two case laboratory experiments were conducted in two flumes simultaneously. The first flume (2.0 m 0.6 m 0.5 m) was set at $22^{\circ}$ and $27^{\circ}$ slope to generate the landslide using rainfall intensity of 70.0 mm/hr. On the other hand, the second flume (1.5 m 0.25 m 0.3 m) was set perpendicularly at the downstream end of the first flume to receive the landslide mass forming landslide dam. The formation of landslide dam was observed at $15^{\circ}$ slope of the second flume. The whole processes including the landslide initiation and movement of the landslide mass into the second channel was captured by three digital cameras. In numerical analysis, a two-dimensional (2D) seepage flow model, a 2D slope stability model (Spencer method) and a 2D landslide dam-geometry evaluation model were coupled as a single unit. This developed model can determine the landslide occurrence time, the failure mass and the geometry of landslide dam deposited in the second channel. The data obtained from numerical simulation results has good agreement with the experimental measurements.

• 산업기술연구
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• 제28권B호
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• pp.185-191
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• 2008

This study tried the 1st, 2nd dimensional numerical analysis according to the pier's shape, size and installing method in order to compare the depth of scour calculation method using the variables calculated by using the 2nd dimensional numerical analysis with the calculated depth of scour value by using the calculated variables by using the 1st dimensional numerical analysis. And then verified the problems occurring when the depth of scour is calculated by using the calculated values by using the 1st dimensional numerical analysis, as calculating the deviation depending on it.

• 대한전기학회논문지:전력기술부문A
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• 제50권9호
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• pp.431-439
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• 2001

This Paper illustrates a new numerical analysis method using a nodal effective load model for nodal probabilistic production cost simulation of the load point in a composite power system. The new effective load model includes capacities and uncertainties of generators as well as transmission lines. The CMELDC(composite power system effective load duration curve) based on the new effective load model at HLll(Hierarchical Level H) has been developed also. The CMELDC can be obtained from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. It is expected that the new model for the CMELDC proposed in this study will provide some solutions to many problems based on nodal and decentralized operation and control of an electric power systems under competition environment in future. The CMELDC based on the new model at HLll will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of MRBTS(Modified Roy Billinton Test System).

• 대한토목학회논문집
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• 제34권3호
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• pp.723-728
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• 2014

세굴방지를 위하여 설치하는 해안구조물의 쇄파효과를 검증하기 위하여 수리조파실험이 실시된다. 하지만 수리조파실험을 실시하기 위해서 사용되는 실험 장치와 해안구조물의 제작에 많은 비용과 시간이 소요된다. 수치해석모델과 수리조파실험의 해석결과를 비교하여 검증하면, 수치모델을 활용하여 쇄파효과를 예측할 수 있고 실험 장치와 해안구조물 제작에 소요되는 비용과 시간을 절약할 수 있다. 본 연구에서는 다면체 사석 구조물을 대상으로 수치해석결과와 수리조파실험 결과의 처오름 및 처내림 높이 비교분석을 수행하였고 해석적 모의 조파실험 모델링 기법을 검증하였다. 또한, 사용한 수치해석 접근 방법을 활용하여 사석의 부피비와 마찰면적을 변화시켜 쇄파효과를 예측하였다.

• 신재생에너지
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• 제2권2호
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• pp.28-36
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• 2006

Numerical analysis of wind turbine scale effect was performed by using commercial CFD code, Fluent. For the numerical analysis of wind turbine, the three dimensional Navier-Stokes solver with various turbulence models was tested. As a turbulence mode, the realizable k-e turbulence model was selected for the simulation of wind turbines. To validate the present method, performance of NREL (National Renewable Energy Laboratory) Phase VI wind turbine model was analyzed and compared with its wind tunnel test and blind test data. Using the present method, numerical simulations for various size of wind tunnel models were carried out and characteristics were analyzed in detail. For wind tunnel test model, the size of nacelle may not be scaled down precisely because of available motor. The effect of nacelle size was also computed and analyzed though CFD simulation. The present results showed the good correlations in pre-stall region but much to be improved in post-stall region. In 2006 and 2007, the performance and the scale effect of standard wind turbine model will be tested in KARI(Korea Aerospace Research Institute) LSWT(Low Speed Wind Tunnel) and the present results will be validated with the wind tunnel data.

• 한국지반공학회논문집
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• 제27권9호
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• pp.25-36
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• 2011

조적식 석축옹벽의 거동 특성을 규명하기 위하여 실내 모형시험과 수치해석을 수행하였다. 실내 모형시험에서 옹벽 블록과 뒤채움재의 변위를 측정하기 위해 PIV 기법의 디지털 이미지 해석을 실시하였다. 유한요소 수치해석을 위해 상용프로그램인 ABAQUS를 사용하였다. 모형시험에서 관찰된 뒤채움재의 변위 발생 과정은 파괴면의 형성이 점진적임을 보여준다. 수치해석 결과에서 석축옹벽의 시공 과정에서 발생하는 전체적인 수평 토압 분포는 기존의 Rankine 이론과 큰 차이가 없지만, 뒤채움재의 내부 마찰각과 석축을 구성하는 석재 간의 마찰각이 작으면 토압의 분포가 불규칙해짐을 확인하였다.

• 한국해양공학회지
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• 제4권1호
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• pp.49-54
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• 1990

This study describes the application of a two dimensional depth integrated numerical model. The explict scheme of finite difference method had been applied to the model of circulation. The nonlinear terms showed a slight difference for the variations of water elevation when calculated grid was small. They were also found to be minor when calculated grid size was increased. For verification of the numerical model, numerical results were compared with predicted values and field data. In the model, the effect of nonlinear advective terms proved not to be significant.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.285-292
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• 2000

Numerical calculation is applied to centrifugal pump at design condition by using commercial code STAR-CD and Tascflow, and these results are compared with experimental data at impeller outlet. Numerical analysis is also performed by changing turbulence model and discretization scheme at design condition using Tascflow. Turbulence model and discretization scheme used to Tascflow are k-$\epsilon$, k-$\omega$ turbulence model and upwind, modified linear profile scheme. W;th the same turbulence model and discretization scheme, two results of STAR-CD and Tascflow are very similar. But there is significant difference in numerical results near hub and shroud of impeller with different kinds of turbulent model and discretization scheme at design condition. And with k- $\omega$ turbulence model and modified linear profile scheme, it is showed that numerical results are very similar to experimental results of impeller outlet

• Computers and Concrete
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• 제25권5호
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• pp.461-470
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• 2020

This paper presents a numerical study on structural behavior of hammer head pier cap beams, extended on verges and reinforced with carbon fiber reinforced polymer (CFRP) plates. A 3-D finite element (FE) model along with a simplified analytical model are presented. Concrete damage plasticity (CDP) was adapted in the FE model and an analytical approach predicting the CFRP anchor strength was adapted in both FE and analytical model. Total five quarter-scaled pier cap beams with various CFRP reinforcing schemes were experimentally tested and analyzed with numerical approaches. Comparison between experimental results, FE results, analytical results and current ACI guideline predictions was presented. The FE results showed good agreement with experimental results in terms of failure mode, ultimate capacity, load-displacement response and strain distribution. In addition, the proposed strut-and-tie based analytical model provides the most accurate prediction of ultimate strength of extended cap beams among the three numerical approaches.