• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.448-453
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• 2001

A commercial CFD code is used to compute the 3-D viscous flow field within the inlet flow concentrator of the newly developed AHU(Air Handling Unit). To improve the performance of the AHU, the inlet air needs to be gradually accelerated to the fan's annular velocity without causing turbulence or flow separation. Three major geometric parameters were selected to specify the inlet shape of the AHU. Several numerical calculations are carried out to determine the influence of the geometric parameters on the performance of the AHU. The performance of the AHU could be measured by the inlet and outlet flow uniformity and the total pressure loss through the inlet flow concentrator. The optimized nondimensionalized velocity profile through the inlet flow concentrator were used for the design of the AHU with the various volume flow rates.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.169-172
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• 2011

Recently, railroad long tunnels are increasing and growing longer due to topological feathers like a lot of mountain in Korea. But fire disaster of a long tunnel cause many people to injury and death. For that reason, at the early design stage of a long tunnel, risk assessment and mitigation measure of risk for satisfying tunnel safety are required. According to the railroad facility safety standard (Korean MLTM Announcement No. 2006-395), risk assessment for railroad-tunnel fire should be performed when design stage. Therefore, various methods of risk assessment for tunnel fire have been studied and applied. In the paper, QRA(Quantitative Risk Analysis) for fire risk assessment by using CFD code is presented and the usefulness of CFD is discussed.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.2
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• pp.151-157
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• 2012

The present study explored the possibilities of the applications of open source libraries to shipbuilding and marine engineering industries. A computational fluid dynamics (CFD) code, termed SNUFOAM, was developed and tested for turbulent flow around a ship, free surface flow around a hull, cavitating flow, and vortex shedding dynamics around a cylinder. The results using the developed CFD codes were compared against existing experimental data and solution of commercial CFD codes. SNUFOAM showed the nearly same results as commercial CFD codes and proved to be an alternative to commercial CFD codes for shipbuilding and marine engineering industries.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.71-80
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• 2020

Before we develop LVAFoam, a CFD software for launch vehicle analysis, we conducted a survey on other CFD softwares. We looked at in-house code and commercial CFD software of other countries that were used as a simulation of launch vehicle's combustor, turbopump and external flow. This research included in-house code solvers, developed by NASA, Mississippi State University, DLR, Bertin Technologies, CNES, CERFACS, and JAXA as well as commercial CFD software from FLUENT, CFX, Advance/FrontFlow/red, GASP, CRUNCH CFD, CFD-ACE+, FINE^TM/Turbo, STAR-CCM+. The simulation cases of launch vehicle analysis from each commercial softwares and introduction of the LVAFoam were presented.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.47-53
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• 2002

The hydraulic design optimization and performance analysis of mixed-flow pumps for waterjet marine vehicle propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study the conceptual design optimization has been formulated with a non-linear objective function to minimize the fluid dynamic losses and then the commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. New designed mixed-flow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree very well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction methods presented herein can be used efficiently as a unified hydraulic design process of mixed-flow pumps for waterjet marine vehicle propulsion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.3
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• pp.220-228
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• 2008

In this study the aerodynamic characteristics of a canard-controlled missile with freely spinning tailfins were investigated by using a semi-empirical method and a CFD code. The mean aerodynamic coefficients for the rolling and roll damping moments were first calculated and then used to predict the roll-rate of freely spinning tailfins. The calculation of roll-rate in the CFD code was carried out by combining a Chimera overset grid system and 6-DOF analysis module. The predicted roll-rate was in good agreement with the experimental data for the roll and yaw canard control inputs. It was also shown that the results are in good agreement with the prediction by a CFD code. This indicates that the semi-empirical method can be used to predict the roll-rate of a canard-controlled missile with freely spinning tailfins.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.13-16
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• 2008

After the collapse of the Tacoma bay bridge at Tacoma Washington, the accurate prediction of aerodynamics became crucial to the sound design of bridges. CFD(Computational Fluid Dynamics) becomes important tool for the prediction on wind effects on the bridge due to the recent development of CFD. The usage of CFD is further prompted by the advantages in using CFD, such as low-cost and fast feed-back of design. In this paper, an unsteady compressible Reynolds averaged Navier-Stokes code is used for the computation of the flow over bridges. Coakley's ��q-${\omega}$ �� two-equation turbulence model is used for the turbulent eddy viscosity. For accurate and stable computations, the local preconditioning method is adapted to the code. Aerodynamic characteristics of a couple bridges are presented to show the validity and the accuracy of the method.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.102-109
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• 2021

Recently, an interest in risk calculation methods has been increasing in Korea due to the establishment of classification code for explosive hazardous area on gas facility (KGS CODE GC101), which is based on the international standard of classification of areas - explosive gas atmospheres (IEC 60079-10-1). However, experiments to check for leaks of combustible or toxic gases are very difficult. These experiments can lead to fire, explosion, and toxic poisoning. Therefore, even if someone tries to provide a laboratory for this experiment, it is difficult to install a gas leakage equipment. In this study we find out differences among actual experiments, CFD by using FLACS and calculation based on classification code for explosive hazardous area on gas facility (KGS CODE GC101) by comparing to each other. We develpoed KGS HAC (hazardous area classification) program which based on KGS GC101 for convenience and popularization. As a result, actual gas leak, CFD and KGS HAC are showing slightly different results. The results of dispersion of 1.8 to 2.7 m were shown in the actual experiment, and the CFD and KGS HAC showed a linear increase of about 0.4 to 1 m depending on the increase in a flow rate. In the actual experiment, the application of 3/8" tubes and orifice to take into account the momentum drop resulted in an increase in the hazardous distance of about 1.95 m. Comparing three methods was able to identify similarities between real and CFD, and also similarities and limitations of CFD and KGS HAC. We hope these results will provide a good basis for future experiments and risk calculations.

• Journal of computational fluids engineering
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• v.19 no.3
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• pp.62-68
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• 2014

The aerodynamic and noise calculations were performed through the CFD-CSD loose coupling methodology. In the loose coupling process, the trimmed rotor airloads were predicted by the in-house CFD code based on unstructured overset meshes, and the trim of the rotorcraft and the aeroelastic deformation of rotor blades were accounted with the CAMRAD II rotorcraft comprehensive code. The set of codes was used to analyze the HART-II baseline test condition. The effect of grid resolution and time step was examined and the loose coupling approach was found to be stable and convergent for the case. Comparison of the resulting sectional airloads, structural deformations, the noise carpets and the wake geometry with experimentally measured data was presented and showed the good agreement.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.22-23
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• 2007

3차원 모델이 가능한 전산유체역학에 기초를 둔 유체 플라즈마 모델링 소프트웨어가 플라즈마 장치 개발에 어떤 도움을 줄 수 있을 것인지 고찰하였다. 몇 가지의 유도 결합 플라즈마용 안테나 구조와 유동의 역할, 공간 및 표면 화학반응의 결과에 대한 자동 최적화 계산의 유용성에 대해서 논한다.