• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.377-381
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• 2010

In 2007 the Nuclear Energy Agency's Committee on the Safety of Nuclear Installations published Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety. This paper provides an overview of the document' contents and highlights a few of its recommendations. The document covers the full extent of a CFD analysis from initial problem definition and selection of an appropriate tool for the analysis, through final documentation of results. It provides advice on selection of appropriate simulation software, mesh construction, and selection of physical models. In addition it contains extensive discussion of the verification and validation process that should accompany any high-quality CFD analysis.

• Tribology and Lubricants
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• v.25 no.5
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• pp.298-304
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• 2009

An angled labyrinth seal is used for the diaphragm-packing-ring seal design of steam turbine due to its leakage reduction characteristic. CFD analysis using FLUENT has been performed to predict leakage and determine an optimum slanted angle which yields the best leakage reduction. Results show that the optimum value of slanted angle is $-30^{\circ}$ independent of number of labyrinth teeth, inlet pressure, and tooth height to pitch ratio. 3D CFD analysis has been performed for predicting leakage of the angled labyrinth seal. Comparing with the result of 2D CFD analysis, 3D CFD analysis shows 1.4% smaller.

• 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.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.101-104
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• 2004

CFD simulation is peformed for 2D and 3D frisbees flying at 10m/s. For convenience of simulation, rotation of 3D model is not considered. CFD results show that pitching moment makes the nose down and holes at the leading and trailing edges improve the lift characteristics of the frisbee.

• International Journal of High-Rise Buildings
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• v.8 no.2
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• pp.107-116
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• 2019

The use of computational fluid dynamics (CFD) is becoming an increasingly popular means to model wind flows in and around buildings. The first published application of CFD to both indoor and outdoor building airflows was in the 1970's. Since then, CFD usage has expanded to include different aspects of building design. Wind tunnel testing (WTT) on buildings for wind loads goes back as far as 1908. Gustave Eiffel built a pair of wind tunnels in 1908 and 1912. Using these he published wind loads on an aircraft hangar in 1919 as cited in Hoerner (1965 - page 74). The second of these wind tunnels is still in use today for tests including building design ($Damljanovi{\acute{c}}$, 2012). The Empire State Building was tested in 1933 in smooth flow - see Baskaran (1993). The World Trade Center Twin Towers in New York City were wind tunnel tested in the mid-sixties for both wind loads, at Colorado State University (CSU) and the [US] National Physical Laboratory (NPL), as well as pedestrian level winds (PLW) at the University of Western Ontario (UWO) - Baskaran (1993). Since then, the understanding of the planetary boundary layer, recognition of the structures of turbulent wakes, instrumentation, methodologies and analysis have been continuously refined. There is a drive to replace WTT with computational methods, with the rationale that CFD is quicker, less expensive and gives more information and control to the architects. However, there is little information available to building owners and architects on the limitations of CFD for flows around buildings and communities. Hence building owners, developers, engineers and architects are not aware of the risks they incur by using CFD for different studies, traditionally conducted using wind tunnels. This paper will explain what needs to happen for CFD to replace wind tunnels. Ultimately, we anticipate the reader will come to the same conclusion that we have drawn: both WTT and CFD will continue to play important roles in building and infrastructure design. The most pressing challenge for the design and engineering community is to understand the strengths and limitations of each tool so that they can leverage and exploit the benefits that each offers while adhering to our moral and professional obligation to hold paramount the safety, health, and welfare of the public.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.320-325
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• 2010

A multiphase CFD analysis is performed to investigate the effect of near-wall grid for simulating a subcooled boiling flow in vertical tube. The multiphase flow model used in this CFD analysis is the two-fluid model in which liquid(water) and vapor(steam) are considered as continuous and dispersed fluids, respectively. A wall boiling model is also used to simulate the subcooled boiling heat transfer at the heated wall boundary. The diameter and heated length of tube are 0.0154 m and 2 m, respectively. The system pressure in tube is 4.5 MPa and the inlet subcooling is 60 K. The near-wall grid size in the non-dimensional wall unit ($y_{w}^{+}$) was examined from 64 to 172 at the outlet boundary. The CFD calculations predicted the void distributions as well as the liquid and wall temperatures in tube. The predicted axial variations of the void fraction and the wall temperature are compared with the measured ones. The CFD prediction of the wall temperature is shown to slightly depend on the near-wall grid size but the axial void prediction has somewhat large dependency. The CFD prediction was found to show a better agreement with the measured one for the large near-wall grid, e.g., $y_{w}^{+}$ > 100.

• Proceeding of EDISON Challenge
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• 2012.04a
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• pp.65-68
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• 2012

본 연구에서는 XFOIL을 사용하여 설계된 30% 두께를 가지며 팁에서의 두께가 코드의 1.5%인 풍력터빈용 에어포일의 공력 특성을 해석하였다. 받음각에 따른 양력 항력 곡선 및 양항비를 XFOIL에서 얻어낸 결과와 EDISON_CFD 해석 결과를 상호 비교 하였다. EDISON_CFD에서의 해석을 위한 격자의 형태를 격자균일성을 생각하여 큰 타원과 작은 타원을 합쳐 만들었다. 수치 기법으로 Roe의 FDS를 선택하여 데이터를 수집하였다. 그 결과로 나타낸 압력계수와 양항비 그래프를 보면 선형 구간에서 양력은 XFOIL 해석 결과와 잘 일치하는 결과를 보여주었다. 그러나 항력에서 약1.5배 정도 EDISON_CFD의 결과가 크게 나옴으로써 양항비의 차이를 보이는 것으로 나타났다. 실속이후에서는 XFOIL의 신뢰도가 떨어지는 경향이 있어 특히 실속이후에서는 CFD의 해석결과가 필요한 것으로 보인다.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1643-1652
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• 2020

To investigate the characteristics of detailed flows in a building-congested district, we coupled a computation fluid dynamics (CFD) model to the local data assimilation and prediction system (LDAPS), a current operational numerical weather prediction model of the Korea Meteorological Administration. For realistic numerical simulations, we used the meteorological variables such as wind speeds and directions and potential temperatures predicted by LDAPS as the initial and boundary conditions of the CFD model. We trilinearly interpolated the horizontal wind components of LDAPS to provide the initial and boudnary wind velocities to the CFD model. The trilinearly interpolated potential temperatures of LDAPS is converted to temperatures at each grid point of the CFD model. We linearly interpolated the horizontal wind components of LDAPS to provide the initial and boundary wind velocities to the CFD model. The linearly interpolated potential temperatures of LDAPS are converted to temperatures at each grid point of the CFD model. We validated the simulated wind speeds and directions against those measured at the PKNU-SONIC station. The LDAPS-CFD model reproduced similar wind directions and wind speeds measured at the PKNU-SONIC station. At 07 LST on 22 June 2020, the inflow was east-north-easterly. Flow distortion by buildings resulted in the east-south-easterly at the PKNU-SONIC station, which was the similar wind direction to the measured one. At 19 LST when the inflow was southeasterly, the LDAPS-CFD model simulated southeasterly (similar to the measured wind direction) at the PKNU-SONIC station.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.121-125
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• 2006

CFD has been used in aircraft development and broaden its influence in various fields of industries. This paper briefly introduces the historical trends of computing system, the overview of CFD applications in Korean Supersonic Trainer Development Program and the demand for CFD software in industry points of view.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.35-41
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• 2010

The temperature of the flight objects in high speed increases due to the aerodynamic heating. MINIVER and CFD approach are used to predict the aerodynamic heating conditions of KSLV-I. MINIVER is based on the empirical method. And the CFD approach predicts the aerodynamic heating conditions after the analysis of the surface temperature and the surface heat flux directly. In this study, the aerodynamic heating conditions using CFD approach are considered. The PLF temperature for these aerodynamic heating conditions is compared with the flight test data of KSLV-I.