• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.1-9
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• 2021

In the present study, the model-scale Propeller Open Water (POW) tests for the propeller of 176K bulk carrier and 8600TEU container ship were conducted through Computational Fluid Dynamics (CFD) simulation. In order to solve the incompressible viscous flow field, the Reynolds-averaged Navier-Stokes (RaNS) equations were employed as the governing equations. The γ-Reθ(gamma-Re-theta) transition model combined with the SST k-ωturbulence model was introduced to describe the laminar-turbulence transition considering the low Reynolds number of model-scale. Firstly, the flow simulation developing over a flat plate was performed to verify the transition modeling, in which the wall shear stresses were compared with experiments and other numerical results. Then, to investigate the effect of the model, the CFD simulation for the POW test was performed and the simulated propeller performance was validated through comparison with the experiment conducted at Korea Research Institute of Ships & Ocean Engineering (KRISO).

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.421-431
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• 2017

A process-centric simulation modeling method has been proposed to define a shipbuilding simulation model. Existing modeling methods have limitations for expressing various production information for a shipyard. The advanced process-centric modeling method proposed in this paper offers an improvement, effectively representing production information and constraints for a shipyard. To achieve this, a method and diagram components to define a process-centric simulation model in detail have been suggested. The modeling method can assign priorities when multiple products and facilities are assigned to the process. And layer concept was applied to express simulation model with hierarchical structure. To verify the effectiveness of the modeling method, comparative analysis has been performed and the actual shipbuilding process has been modeled using the proposed method. When a single facility was used for various purposes, we found that the proposed method was more advantageous than existing methods. As a result, it was possible to express constraints and flows that were difficult to identify with existing process-centric simulation modeling methods, and the methods were improved for use in shipyard production planning verification simulations.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.41-50
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• 2012

In this study we first explain details of the semiconductor manufacturing processes and cluster tools. Then we discuss the problems in current fab layout and cluster tool architecture. As a solution to these problems, we propose the ILE (In-Line EFEM) architecture in which wafer movements are conducted through interconnected EFEMs (Equipment Front End Modules) instead of AMHS (Automated Material Handling System). Then we model the pilot ILE system using discrete event simulation and analyze the cycle time. Finally we compare three different scenarios of equipment layout in the ILE system in terms of cycle time.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.82-88
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• 2005

There are plenty of optimization models for the signal-system of a single intersection and area traffic. Some of those models are adopted for the real traffic signal control system. The simulators for a single crossroad have been developed, so that we could evaluate optimization models and traffic control systems. However, the simulators for the area traffic are still being developed. Therefore, there are some limitations in the analysis and evaluation for area traffic control systems, The area traffic is consist of several intersections interconnected which are very complicated and many traffic strategy are adopted for the control system. This paper features an effective area traffic control system by High Lever Architecture(HLA) which is a new developed simulation tool. In this paper, we discuss the design of HLA-based area traffic control simulation. We describe technical motivations for the HLA, the key elements of the architecture and how they are minimum and essential to the goal of reuse and interoperability.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.53-58
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• 2013

Recently, some fluid-structure interaction (FSI) problems involving the fluid impact loads interacting with structures, such as sloshing, slamming, green-water, etc., have been considered, especially in the ocean engineering field. The governing equations for both an elastic solid model and flow model were originally derived from similar continuum mechanics principles. In this study, an elastic model based on a particle method, the MPS method, was developed for simulating the FSI problems. The developed model was first applied to a simple cantilever deflection problem for verification. Then, the model was coupled with the fluid flow model, the PNU (Pusan National University modified)-MPS method, and applied to the numerical investigation of the coupling effects between a cantilever and a mass of water, which has variable density, free-falling to the end of the cantilever.

• Journal of the Korea Society for Simulation
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• v.9 no.4
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• pp.25-40
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• 2000

The cost of simulation modeling, the expertise required, and the pains of starting a new each time are impediments to more wide spread adoption of simulation technology. In addition, one of the most critical problems in the field of computer simulation today is the lack of published models and physical objects within the World Wide Web (WWW) allowing such distribution. From the viewpoint of WWW as distributed model repositories, it can be assumed that very many simulation models exist on the web. This paper is based on the premise that WWW is a distributed repository. Design Pattern, web-oriented technology like Java and CORBA, which are especially to cope with distributed objects, are introduced and discussed in detail for integration of simulation model. In this paper an architecture of model integration is proposed, which presents the whole procedure of model integration and how the Internet technologies are connected in. The central focus of this research is on the technical realization of integrating simulation models as distributed objects

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.103-118
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• 2006

At the initial design stage, the generation process of the production material information of a building block and the simulation process of the block erection, which are required to perform the production planning and scheduling, have been manually performed using 2D drawings, based on the data of parent ships, and subjective intuition from past experience. To make these processes automatic, the accurate generation method of the production material information and the convenient simulation method of the block erection based on the initial hull structural model(3D CAD model), were developed in this study. Here, the initial hull' structural model was generated from the initial hull structural CAD system early developed by us. To evaluate the developed methods. these methods were applied to corresponding processes of a deadweight 300,OOOton VLCC. As a result. it was shown that the production material information of a building block can be accurately generated and the block erection can be conveniently simulated in the initial design stage.

• Journal of the Korea Society for Simulation
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• v.9 no.3
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• pp.65-75
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• 2000

In recent years, significant advances in computers and communication technologies have made multimedia services feasible. As a result, various queuing models and cost models on architecture and data placement for multimedia server have been proposed. However, these analytical techniques use only probabilistic models to represent the behavior of a system, and then they have several limitations like accuracy. Simulation is a viable alternative to analytical model. It avoids many of the limitations associated with analytical techniques, allowing for more precise representation of system attributes like workload in program code. In this paper, we propose a simulation test bed that can evaluate performance of real-time multimedia server by using simulation model.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.553-571
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• 2019

Geometric variation including welding distortion accumulates as many parts are joined together, ultimately affecting the final product. This variation is then subjected to correction, which requires considerable effort, time, and cost. This variation can be categorized as in-plane/out-of-plane variation. To date, studies on variation simulation have largely focused on the out-of-plane variation, however the variation generated in the in-plane direction requires more time and efforts to correct afterwards. This research aims to construct a variation simulation model considering both the in-plane and out-of-plane variations. A geometric analysis was performed to derive an equation that reflects the coupling effect of the out-of-plane variation on the in-plane variation. The proposed model is validated with case study analysis and the results shows that good fidelity in predicting and diagnosing the in-plane variation during the block assembly process considering welding distortion.

• Journal of Ocean Engineering and Technology
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• v.21 no.1 s.74
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• pp.64-68
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• 2007

Recently, there has been considerable research in the field of application of Laser-Arc hybrid welding for superstructures, such as ship-structures, transport vehicles etc. However, the study on heat distribution and welding residual stress of hybrid weld by numerical simulation leaves much to be desired. Therefore, in this study, an optimized welding condition and numerical simulation for hybrid welding, using previous numerical analysis to calculate the heat source for hybrid welding, has been analyzed. For this purpose, fundamental welding phenomena of the hybrid process, using Laser and, is investigated. In order to calculate temperature and residual stress distribution in hybrid welds, a finite element heat source model is developed on the basis of experimental results and characteristics of temperature. Residual stress distribution in hybrid welds are understood from the result of simulation, and compared with the experimental values.