• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2401-2405
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• 2008

In the present study, a three-dimensional least square/level set based two-phase flow code was developed for the simulation of three-dimensional sloshing problems using finite element discretization. The present method can be utilized for the analysis of a free surface flow problem in a complex geometry due to the feature of FEM. Since the finite element method is employed for the spatial discretization of governing equations, an unstructured mesh can be naturally adopted for the level set simulation of a free surface flow without an additional load for the code development except that solution methods of the hyperbolic type redistancing and advection equations of the level set function should be devised in order to give a bounded solution on the unstructured mesh. From the numerical experiments of the present study, it is shown that the proposed method is both robust and accurate for the simulation of three-dimensional sloshing problems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.359-363
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• 2004

Numerous studies have been performed to analyze various phenomena of human's walking, gait. In the present study, unrecognized walking and recognized walking were analyzed by three dimensional motion capture system(VICON motion system Ltd., England) and simulated by computer program. Two normal males participated in measuring the motion of unrecognized and recognized walking. Six infrared cameras and four force plates were used and sixteen reflective markers were attached to the subject to capture the motion. A musculoskeletal model was generated anatomically by using ADAMS(MSC software corp., USA) and LifeMOD(Biomechanics Research Group Inc, USA). The inverse dynamic simulation and forward dynamic simulation were also performed. The result of simulation was similar to the experimental result. This study provides the base line for dynamic simulation of the falling walking. It will be useful to simulate various another pathologic gaits for old peoples.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.121-131
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• 2008

Two dimensional road design is connoting danger factor because different point between design standard and driver's reaction. Consequently two dimensional road design is difficult to recognize problem that happen beforehand when before construction. Therefore three dimensional road design that can grasp problem after completion is required. In this study, three dimensional road was designed to evaluate road that is designed. Road designed by Inroad that is road design program. DTM is created using digital map and elevation data. Three dimensional road was designed by integrated DTM of road and topography. Road design evaluation was performed in three dimension. Driving simulation and sight distance assessment were carried out to estimate stability of alignment. Shadow simulation was executed on icy road section for bad section of icy road surface. As a result of evaluation, this study could confirm shape of road after completion. And sight distance could be calculated and visually confirmed. Also, icy road sections were extracted through shadow simulation.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.8
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• pp.41-51
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• 1997

The device simulator (BANDIS) which can analyze efficiently the electrical characteristics of the semiconductor devices under the three dimensional stationary conditions on the IBM PC was developed. Poisson, electon and hole continuity equations are discretized y te galerkin method using a tetrahedron as af finite element. The frontal solver which has exquisite data structures and advanced input/output functions is dused for the matrix solver which needs the highest cost in the three dimensional device simulation. The discretization method of the continuity equations used in BANDIS are compared with that of the scharfetter-gummel method used in the commercial three-dimensional device. To verify an accuracy and the efficiency of the discretization method, the simulation results of the PN junction diode and the BJT from BANDIS are compared with those of the commercial three-dimensiional device simulator such as DAVINCI. The maximum relative error within 2% and the average number of iterations needed for the convergence is decreased by more than 20%. The total simulation time of the BJT with 25542 nodes is decreased to about 60% compared with that of DAVINCI.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.19-22
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• 2014

As computer technology develops and this is applied to medical image field, three dimensional image reconstruction technology using computer simulation is utilized in various categories that include anatomical study and biomechanics study of human body. Especially orthopedic surgeons are able to investigate biomechanical function and be provided information for operations with this technology in terms of ligament reconstruction of knee. And this technology can be utilized in preparing preoperative planning and instructions and training. This review is about three dimensional image reconstruction technology which is utilized in ligament reconstruction of knee.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.217-226
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• 1998

A numerical study has been carried out for two- and three-dimensional buoyant turbulent flow in a stairwell model. The Reynolds-averaged Navier-Stokes and energy equations are solved with the authors'own computer program. Two models by the Boussinesq approximation and the density-gradient form are used for buoyancy terms in the governing equations. Two- and three-dimensional predictions of the velocity and temperature fields are presented and the results are compared with experimental data. Comparisons have also been made in detail with two-dimensional predictions. Two-dimensional and three-dimensional simulations have predicted the overall features of the flow satisfactorily. A better agreement with experiment is achieved with three-dimensional simulations.

• Transactions of Materials Processing
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• v.6 no.5
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• pp.408-415
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• 1997

The backward tracing scheme of the finite element analysis, which is counted to be unique and useful for process design in metal forming, has been developed and applied successfully in industry to several metal forming processes. Here the backward tracing scheme is implemented for process design of three-dimensional plastic deformation in metal forming, and it is applied to a precision coining process. The contact problem between the die and workpiece has been treated carefully during backward tracing simulation in three-dimensional deformation. The results confirm that the application of the developed program implemented with backward tracing scheme of the rigid plastic finite element leads to a reasonable initial piercing hole configuration. It is concluded that three-dimensional extension of the scheme appears to be successful for industrial applications.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.469-476
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• 2019

Robotic motion is designed by the rotation and the translation of multiple joint coordinates in a three-dimensional space. Joint coordinates are generally modeled by homogeneous transform matrix. However, the complexity of three dimensional motions prefers the visualization methods based on simulation environments in which models and generated motions work properly. Many simulation environments have the limitations of usability and functional extension from platform dependency and interpretation of predefined commands. This paper proposes the web-based three dimensional simulation environment toward high user accessibility. Also, it covers the small size web server that is linked with Python script. The non linearities of robot control apply to verify the computing efficiency, the process management, and the extendability of user scripts.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.113-122
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• 1987

A numerical simulation technique of three-dimensional finite difference model is developed to study the groundwater flow system in Dcjima, an upland area which faces Kasumigaura Lake. For general perspectives of the groundwater flow system, a steady state three-dimentional model is simulated. For the sedimentary mud formations which are found in the representative formation, three situations of hydraulic conductivity are considered, representing an isotropic condition and situations where the horizontal permeability is equal to 10 times and 100times of the vertical one. The finite difference grid used in the simulation has 60x50x30=90,000 nodes. A converged solution with a tolerance of 0.001 meter of hydraulic head is set. Having determined the flow net by using a steady state three-dimensional model. the results for the three cases of hydraulic conductivity are compared with the results of tracer methods (Bae and Kayane 1987) With the aid of four representative vertical cross-sections, groundwater flow systems in the study area are assumed. Water balances for the three cases indicate very good agreement between total recharge and discharge in each case Analyses of groundwater flow system based on the tritium concentrations and water quality measurements (Bae and Kayane 1987) are confirmed by the numerical simulation and the results obtained by these two methods appeared to be in close agreement.

• Korean Chemical Engineering Research
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• v.55 no.5
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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.