• 대한조선학회논문집
• /
• 제42권4호
• /
• pp.350-356
• /
• 2005

Prediction of green water loads acting on the bow deck is au essential part for the design of bow structures against the green water impact. Proper technique of the green water simulation is highly required for the prediction of green water loads. in this paper, the green water flow on bow deck is simulated by FDM(finite difference method). Using the results of green water simulation, impact load on bow deck is calculated. Also, experiments are carried out to compare with the numerical calculation. Through the comparisons between experimental results and numerical results, it is verified that the present numerical tool is adequate as a practical calculation tool for the green water problem.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.143-144
• /
• 2011

• 한국유체기계학회 논문집
• /
• 제15권1호
• /
• pp.27-35
• /
• 2012

A numerical simulation for particle collection efficiency in a wire-plate electrostatic precipitator (ESP) has been performed. Method of characteristics and finite differencing method (MOC-FDM) were employed to obtain electric field and space charge density, and lattice boltzmann method (LBM) was used to predict the Electrohydrodynamic (EHD) flow according to the ion convection. Large eddy simulation (LES) was considered for turbulent flow and particle simulation was performed by discrete element method (DEM) which considered field charging, electric force, drag force and wall-collision. One way coupling from FDM to LBM was used with small and low density particle assumption. When the charged particle collided with the collecting plate, particle-wall collision was calculated for re-entertainment effect and the effect of gravity force was considered.

• 열처리공학회지
• /
• 제14권4호
• /
• pp.228-234
• /
• 2001

The present study was an attempt for systematic data conversion between FDM and FEM in order to evaluate the thermal stress distribution during quenching process. It has been generally recognized that FDM is efficient in flow and temperature analysis and FEM in that of stress. But it induced difficulty and tedious work in analysis that one uses both FDM and FEM to take their advantages because of the discrepancy of nodes between analysis tools. So we proposed field data conversion procedure from FDM to FEM in 3-dimensional space, then applied this procedure to analysis of quenching process. The simulation procedure calculates the distributions of temperature and microstructure using FDM and microstructure evolution equations of diffusion and diffusionless transformation. FEM was used for predicting the distributions of thermal stress. The present numerical code includes coupled temperaturephase transformation kinetics and temperature-microstructure dependent material properties. Calculated results were compared with previous experimental data to verify the method, which showed good agreements.

• 한국안전학회지
• /
• 제10권2호
• /
• pp.56-63
• /
• 1995

A simulation of contaminant dispersion in a water reservoir has been done using 2-D finite difference method(FDM). The steady state velocity field of the reservoir was computed using stream function-vorticity formulation of Wavier-Stokes equation and continuity equation. Based on the computed steady state velocity field, the transient convective diffusion equation of the contaminant dispersion was computed. For the 1m$\times$1m reservoir model with inlet and outlet attached, it was shown that the center of circulation located toward right. For the numerical values of v =0.01($\textrm{cm}^2$/s) and D=0.6($\textrm{cm}^2$/s) and the flow of 50($\textrm{cm}^3$/s ), it was determined that the outflow had to be shut down in 18 seconds to prevent from severe pollution. Also the required time was computed to be 6 seconds for the inflow of 100 ($\textrm{cm}^3$/s). The result of this study is considered, hopefully, to be useful for the design of the water reservoir systems that are the subjects to various contamination.

• 한국해양공학회지
• /
• 제4권1호
• /
• pp.55-61
• /
• 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.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2006년도 학술발표회 논문집
• /
• pp.1914-1918
• /
• 2006

나날이 해안의 개발이 증대되어지고 있는 시점에, 안전한 항만 구조물의 설치와 그와 관련된 설비의 중요성이 증폭되고 있다. 특히 항내의 안전을 위해서 방파제의 건설이 필요한데 이에 따른 파의 회절현상을 이해함으로써 항내에서의 파고 등을 예측하는데 도움이 되리라 생각한다. 파의 변형을 예측하기 위해서는 수치적인 방법인 FDM을 사용하여 포물선형 완경사방정식을 차분함으로써 해를 얻을 수 있었고, 적용대상으로서 개구부가 있는 방파제와 반무한방파제를 선정 하였다. 각각 파의 입사각을 $0^{\circ},\;30^{\circ},\;60^{\circ}$로 하여 이 후 파의 변형을 예측하였고, 이의 Diffraction Coefficient와 Amplitude 결과를 도시한 후 Penny와 Price의 해 및 Memos의 해와 비교하였다.

• Journal of Power Electronics
• /
• 제19권6호
• /
• pp.1591-1600
• /
• 2019

In this paper, a practical SPICE model for an IGBT and a PiN diode is proposed based on the Finite Differential Method (FDM). Other than the conventional Fourier model and the Hefner model, the excess carrier distribution can be accurately solved by a fast FDM in the SPICE simulation tool. In order to improve the accuracy of the SPICE model, the Taguchi method is adopted to calibrate the extracted parameters. This paper presents a numerical modelling approach of an IGBT and a PIN diode, which are also verified by SPICE simulations and experiments.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권8호
• /
• pp.433-442
• /
• 2004

Various models and various boundary conditions have been suggested for fluid transport simulations of high density plasma discharges such as the inductively coupled plasma discharge. In this work, we compare the various models using one-dimensional simulations based on the FDM(finite difference method), the upwind scheme, the power-law scheme, and the dielectric relaxation scheme［l］ Comparing the exactness, the numerical stability and the efficiency of the various models. the most adoptable model is suggested.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.1441-1446
• /
• 2009

Numerical analysis is a powerful method in evaluating the soil-pile-structure interaction under the dynamic loading, and this approach has been applied to the practical area due to the development of computer technology. Finite Difference Method, one of the most popular numerical methods, is sensitive to the shape and the number of mesh. However, the trial and error approach is conducted to obtain the accurate results and the reasonable simulation time because of the lack of researches about mesh size and the number. In this study, FLAC 3D v3.1 program(FDM) is used to simulate the dynamic pile model tests, and the numerical results are compared with the 1G shaking table tests results. With the different size and shape of mesh, the responses of pile behavior and the simulation time are estimated, and the optimum mesh sizes in dynamic analysis of single pile is studied.