• Computers and Concrete
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• 제12권4호
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• pp.431-442
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• 2013

This study attempted to find a proper method applicable to simulating practical equifield lines of two-dimensional Accelerate Lithium Migration Technique (ALMT), and evaluate the feasibility of using the theoretical ion migration model of one-dimensional ALMT to predict the ion migration behavior of two-dimensional ALMT. The result showed that the electrolyte or carbon plate can be used as matrix to draw equifield line graph similar to that by using mortar as matrix. Using electrolyte electrode module for simulation has advantages of simple production, easy measurement, rapidness, and economy. The electrolyte module can be used to simulate the equifield line distribution diagram in practical two-dimensional electrode configuration firstly. Then, several equifield line zones were marked, and several subzones under one-dimensional ALMT were separated from various equifield line zones. The theoretical free content distribution of alkali in concrete under two-dimensional electric field effect could be obtained from duration analysis.

• 터널과지하공간
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• 제19권3호
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• pp.167-173
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• 2009

지하비축기지는 터널의 규모와 건설공정의 복잡성, 지질 및 지반공학적인 문제들로 인해 가장 난해한 지하공간건설 프로젝트로 알려져 있다. 최근 복잡한 지하구조를 3차원으로 가시화하고, 건설 자원과 지반조건 그리고 공정계획을 고려한 4차원 시뮬레이션을 활용하여 건설공정을 최적화하는 기술이 지하비축기지 건설 프로젝트에 적용되었다. 이 사례연구는 지하구조의 3차원 모델링을 통해 작업자가 복잡한 지하 현황을 쉽게 이해하고, 정확한 3차원 공간상에서 지질자료를 분석하고 검토할 수 있도록 도와줄 수 있음을 보여주고 있다. 또한 건설공정과 실제 공기를 고려한 4차원 시뮬레이션을 활용하여 자재와 버력의 반출입에서 나타날 수 있는 bottle neck의 위치와 시점을 판단하거나 일일 공사비의 변동을 검토하고, 작업조와 투입장비의 수, 터널 시공방향 및 굴착 착수 시점, 버력 및 자재의 운반경로를 검토함으로써 공정의 최적화를 달성할 수 있었다.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.698-703
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• 2017

Bubble flow characteristics in fluidized beds were analyzed by CPFD simulation. A fluidized bed, which had the size of $0.3m-ID{\times}2.4m-high$, was modeled by commercial CPFD $Barracuda^{(R)}$. Properties of bed material were $d_p=150{\mu}m$, ${\rho}_p=2,330kg/m^3$, and $U_{mf}=0.02m/s$. Gas was uniformly distributed and the range of superficial gas velocity was 0.07 to 0.16 m/s. Two other geometries were modeled. The first was a three-dimensional model, and the other was a two-dimensional model of $0.01m{\times}0.3m{\times}2.4m$. Bubble size and rising velocity were simulated by axial and radial position according to superficial gas velocity. In the case of three-dimensional model, simulated bubble rising velocity was different from correlations, because there was zigzag motion in bubble flow, and bubble detection was duplicated. To exclude zigzag motion of bubble flow, bubble rising velocity was simulated in the two-dimensional model and compared to the result from three-dimensional model.

• Fibers and Polymers
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• 제7권4호
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• pp.436-441
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• 2006

An integrated platform for garment drape simulation system has been developed. In this system, garment patterns from conventional two-dimensional CAD systems can be assembled into a three-dimensional garment on a parametrically resizable realistic human body model. A fast and robust particle-based physical calculation engine has been developed for garment shape generation. Then a series of geometric and graphical techniques were applied to create realistic impressions on simulated garments. This system can be used as the rapid prototyping tool for garments in the future quick-response system.

• 한국해양공학회지
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• 제4권1호
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• pp.55-61
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• 1990

For the tracking of three dimensional free surface motions, a method referred to as the Volume of Fluid(VOF) algorithm is extended. In order to calculate the slope of three dimensional free surface which is the most important for the advection algorithm that decides the amount of fluid from cell to cell and for the application of free surface boundary condition, a simple method utilizing two dimensional slope informations is introduced. The extended algroithm is tested by demonstrating the simulation of a propagating sinusoidal wave through the channel whose width changes abruptly.

• 패션비즈니스
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• 제15권6호
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• pp.101-112
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• 2011

Three-dimensional(3D) virtual clothing simulation system may require the use of physical, mechanical, and configurational data in order to mimic the actual clothing with high degree of realism. Therefore the 3-dimensional scanning system based on optical methods was adopted to extract the 3-dimensional data of the fabric surface. In this study, the appearances of the 3-dimensionally transformed textile fabrics via several finishing procedures were investigated using a 3D scanning system. The wool gauze fabrics treated with the shrink-proof finishing and the felting process showed height changes up to 4.5mm. The 3-dimensional configuration may be objectively described by the use of mesh generation from the scanned output. The generated mesh information may further be utilized in the 3D virtual clothing simulation system for accurate description of the fashionable textile materials used in the simulation system.

• 한국분말재료학회지
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• 제7권4호
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• pp.189-196
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• 2000

Effect of ball filling ratio on the behavior of balls motion and their collision characteristic in a tumbler-ball milling of metal powder are investigated by a computer simulation. The discrete element method and the extended Kelvin model composed of nonlinear spring and nonlinear dashpot were employed in the simulation. It can be possible that analysis of the individual balls motion in a three-dimensional actual mill by the two-dimensional model simulation, since the simulated trajectories of ball paths are in relatively good agreement with the actual ones. It knows that the balls motion in the tumbler-ball mill is strongly influenced by the surface conditions of the balls and mill container wall. The energy consumption of the individual balls during impact and the impact frequency of the individual balls increased with an increase in the ball filling ratio and showed maximum values at about 50-60% ball filling ratio, and then decreased.

• Coupled systems mechanics
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• 제8권4호
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• pp.339-350
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• 2019

A numerical simulation of the incompressible multiphase hydraulic jump flow was performed to compare the interface prediction through the use of the three RANS turbulence models: $k-{\varepsilon}$, $RNGk-{\varepsilon}$ and SST $k-{\omega}$. A three dimensional no submerged hydraulic jump and a two dimensional submerged hydraulic jump were modeled. Both the geometry and the mesh were created using the open source Gmsh code. The project's geometry consists of a rectangular channel with length and height differences between the two dimensional and three dimensional simulations. Uniform hexahedral cells were used for the mesh. Three refining meshes were constructed to allow to verify simulation convergence. The Volume of Fluid (abbr. VOF) method was used for treatment of the air-water surface. The turbulence models were evaluated in three distinct set up configurations to provide a greater accuracy in the flow representation. In the two-dimensional analysis of a submerged hydraulic jump simulation, the turbulence model RNG RNG $k-{\varepsilon}$ provided a better interface adjust with the experimental results than the model $k-{\varepsilon}$ and SST $k-{\omega}$. In the three-dimensional simulation of a no-submerged hydraulic jump the k-# showed better results than the SST $k-{\omega}$ and RNG $k-{\varepsilon}$ capturing the height and length of the ledge with a better fit with the experimental results.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.223-233
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• 2002

The air distribution duct with multiple outlets is an essential part of automotive air-conditioning system In a bus. The estimation of airflow rate in an automotive air-conditioning duct is typically very complicate due to large variations in cross-sectional area and abrupt changes in flow direction, as well as unbalanced distribution of the flow. In this paper, the flow characteristic in a duct with multiple outlets is investigated through experiment, CFD simulation and a one-dimensional simulation. Numerical simulations have been performed for two simplified air conditioning ducts with multiple outlets used in a medium bus. The three dimensional Navier-Stokes code was used to evaluate the overall pressure, velocity Held, and distribution rate at each diffuser according to the change of various design parameters such as ratio of cross-sectional area and radius of bifurcated region. In addition, a one-dimensional program based on Bernoulli equation was developed to obtain optimized diffuser area required to equalize discharge flow rate at each outlet. As a result of this study, optimized diffuser area of design variable by one-dimensional program was very reasonable as compared to the trend deduced from CFD Simulation. Therefore, the simple and convenient one-dimensional analysis developed in this study can be applied in practical design procedure for air-conditioning duct.

• Radiation Oncology Journal
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• 제25권1호
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• pp.26-33
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• 2007

목 적: 좌측 조기유방암으로 보존수술 후 2차원 또는 3차원 모의치료를 통해 방사선치료를 받은 환자들에서 SPECT (single photon emitted computerized tomography) 영상을 이용하여 심근관류결손의 부위와 빈도를 비교 평가하고자 하였다. 대상 및 방법: 2002년 1월부터 2003년 8월까지 AJCC 병기 T1-T2N0M0인 좌측 조기유방암으로 진단되어 외과에서 보존수술 및 화학요법 후 방사선치료를 시행하였던 32명의 환자들을 대상으로 하였다. X선 투시기를 이용한 2차원 모의치료를 통해 방사선치료를 받은 환자들과 컴퓨터단층촬영 기반의 3차원 모의치료 방법을 이용했던 환자들을 구분하여 연구를 진행하였다. 이들을 대상으로 최소 3년 이상의 추적관찰 기간 후에 technetium-99m-sestamibi gated perfusion SPECT를 시행하여 각 군에서의 심근관류결손의 부위와 빈도를 비교 평가하였고, 각 환자들에서의 심벽의 운동상태와 좌심실의 박출량을 측정하여 분석하였다. 또한 모의치료 과정에서 방사선에 피폭되는 심장영역을 각 군에서 측정하여 심근관류결손과의 상관관계를 알아보았다. 결 과: SPECT 영상 결과, 심근관류결손이 확인된 경우는 전체 32명의 환자 중 11명(34.4%)이었다. 2차원 모의치료를 받은 15명의 환자 중 7명(46.7%)에서, 3차원 모의치료를 받은 17명의 환자 중 4명(23.5%)에서 관류결손이 발견되었는데, 3차원 모의치료를 이용한 환자들에서 심근관류결손의 빈도가 통계적으로 유의하게 낮았다(p=0.0312). 심근관류결손이 확인된 11명 중, 심첨부 결손을 보인 경우가 10명으로 대부분을 차지했다. 심벽의 운동상태와 심실박출량은 모두 정상이었으며, 방사선 조사야에 포함된 심장영역은 3차원 모의치료 군에서 보다 작았으나 양군에서의 심근관류결손과의 통계적 유의성은 확인할 수 없었다. 결 론: 저자들은 이번 연구를 통해 좌측 조기유방암 환자에서 보존수술 후 방사선치료 시 전산화단층촬영 모의치료기를 이용한 3차원 모의치료 방법을 이용하면 심근에 대한 조사용적을 줄일 수 있어 심근관류결손의 빈도를 낮출 수 있음을 확인하였다. 그러나 심근관류스캔상의 결손과 향후 임상적인 허혈성 심장질환으로의 발전 또는 이로 인한 사망률의 증가와의 연관성은 장기간의 추적관찰과 전향적 임상연구를 통해 확인할 필요가 있겠다.