• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.185-193
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• 2012

Recently rapid urbanization facilitates development of high-rise building complex including apartment and office building in urban area. Many problems related with high -rise building are reported. Especially, unpleasant strong winds in pedestrian area are frequently encountered around the high-rise building. CFD simulation methods are used to analyze the wind environment of pedestrian level in high-rise building block. However, the results show differences between CFD and measurement. This difference is attributed to improper use of CFD. Conventional CFD simulation for wind environment around high-rise building does not describe the effect of trees, shrubs and plants near ground which affect the wind environment of pedestrian level. Canopy model can be used to reproduce the aerodynamic effects of trees, shrubs and plants near ground. In this paper, CFD simulation methods coupled with the tree canopy model to predict wind environment of pedestrian level in high-rise residential building block were suggested and the validity was analyzed by comparison between measurement and CFD results.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.345-353
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• 2012

Recently rapid urbanization facilitates development of high-rise building complex including apartment and office building in urban area. Many problems related with high-rise building are reported. Especially, unpleasant strong winds in pedestrian area are frequently encountered around the high-rise building. CFD simulation methods are used to analyze the wind environment of pedestrian level in high-rise building block. However the results show differences between CFD and measurement. The reason for the difference is that conventional CFD simulation couldn't consider the effect of trees, shrubs and plants which affect the wind environment. Canopy model is a solution to solve the limitation of CFD analysis. In this paper, the canopy model to predict wind environment of pedestrian level by CFD simulation will be proposed and the validity will be analyzed by comparison of measurement and CFD prediction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.132-138
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• 2003

In order to evaluate properly ship motion relating to the berthing maneuver, the hydrodynamic forces acting on ship hull in berthing maneuver need to be estimated rightly. CFD has been employed for time-domain simulation of transient flow induced by Wigley model moving laterally from rest in shallow water. The numerical solutions successfully captured not only the characteristics of the transitional hydrodynamic forces but also some interesting features of the flow field around a berthing ship according to the water depth. In this paper, the consideration is carried out on the approximate formula based on the CFD results, which can estimate hydrodynamic forces especially lateral drag coefficient starting from the rest to the uniform movement.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.24-24
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• 2018

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.98-104
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• 2007

This study is related with the fire risk assessment for fire area at nuclear power plant by use of FDS (Fire Dynamics Simulator) that is a computational fluid dynamics (CFD) model of fire-driven fluid flow. The major purpose of this research is to analyze the sensitivity of the fire modeling when the heat release rate that is an important input variable is changed as well as when the grid size that is a critical factor of the fire model is modified. The result is presented at the conclusion with some comments for CFD model application.

• Korean Journal of Remote Sensing
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• v.38 no.5_3
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• pp.851-861
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• 2022

In this study, we analyzed the effects of trees planted in urban areas on PM_2.5 reduction using a computational fluid dynamics (CFD) model. For realistic numerical simulations, the meteorological components(e.g., wind velocity components and air temperatures) predicted by the local data assimilation and prediction system (LDAPS), an operational model of the Korea Meteorological Administration, were used as the initial and boundary conditions of the CFD model. The CFD model was validated against, the PM_2.5 concentrations measured by the sensor networks. To investigate the effects of trees on the PM_2.5 reduction, we conducted the numerical simulations for three configurations of the buildings and trees: i) no tree (NT), ii) trees with only drag effect (TD), and iii) trees with the drag and dry-deposition effects (DD). The results showed that the trees in the target area significantly reduced the PM_2.5 concentrations via the dry-deposition process. The PM_2.5 concentration averaged over the domain in DD was reduced by 5.7 ㎍ m^-3 compared to that in TD.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.58-65
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• 2012

Various models are currently applied to predict the dispersion of leaked combustible gas and overpressure from a vapor cloud explosion(VCE). However, those models use simple approaches where topography and barriers of anti-leakage facilities and the effects of buildings were not sufficiently taken into considerations. For this reason, this study has proposed the dispersion process of leaked gas, distribution patterns, and flames and overpressure generated from gas explosions in 2D and 3D virtual spaces by reviewing more accurately analyzable computational fluid dynamics (CFD) model by considering various variables including combustion types of leaked substances, geometry of facility, warm currents, barriers, the influence of wind, and others. The CFD analysis results are anticipated to be usefully applied for the risk analysis of explosion and for the risk-based design.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.659-667
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• 2011

Wind tunnels tests have been evaluating wind load estimation by discussing the most important design elements in very tall buildings. Such tests have some uncertainties, however, with respect to the data of the reduced model and the calculated empirical values. In contrast, CFD analysis can simulate the actual scale and shorten the time of simulation. Nevertheless, the utilization of CFD analysis is negligible because of its low reliability. In this paper, the reliability of CFD analysis will be proven by comparing the results of a wind tunnel test and CFD analysis for the prototype models shown in previous studies. The effect of the turbulence intensity on the reliability is also presented.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.132-145
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• 2017

Shock loss was not applied for the tunnel ventilation of road tunnel in the past. However, pressure losses due to the shock loss can be significant in network double-deck road tunnel in which combining and separating road structures exist. For the optimum ventilation design of network double-deck road tunnel, this study conducted 3D CFD numerical analysis for the shock loss at the combining and separating flows. The CFD model was made with the real-scale model that was the standard section of double-deck road tunnel. The shock loss coefficient of various combining and separating angles and road width was obtained and compared to the existing design values. As a result of the comparison, the shock loss coefficient of the $30^{\circ}$ separating flow model was higher and that of the two-lane combining flow model was lower. Since the combining and separating angles and road width can be important for the design of shock loss estimation, it is considered that this study can provide the accurate design factors for the calculation of ventilation system capacity. In addition, this study conducted 3D CFD analysis in order to calculate the shock loss coefficient of both combining and separating flows at flared intersection, and the result was compared with the design values of ASHRAE. The model that was not widened at the intersection showed three times higher at the most, and the other model that was widened at the intersection resulted two times higher shock loss coefficients.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.59-62
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• 2001

여름철 온실내 고온 문제를 해결하기 위해 이용되는 자연환기형 포그냉방은 환기가 충분치 못할 경우 온실 내부의 습도가 증가하여 증발 효율이 떨어지는 문제가 발생한다. 제습장치를 이용하여 온실 내부의 상대습도를 낮추면 증발 냉각 효율을 높일 수 있을 것으로 생각된다. 본 연구에서는 제습장치를 이용한 포그냉방 온실에 대한 CFD 모델을 개발하여 온실의 열환경 및 수분 환경을 분석하고자 한다. (중략)