• Title/Summary/Keyword: Computational Fluid Dynamics

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Air Flow in a Neonate Incubator: Flow Visualizations, Hot-Wire Velocity Measurements and Computational Fluid Dynamics (신생아 보육기의 공기유동에 관한 유동가시화, hot-wire 속도계측 및 전산유동 해석)

  • Kim, Young-Ho;Kwon, Chi-Ho;Yoo, Seoung-Chool
    • Proceedings of the KSME Conference
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    • pp.162-168
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    • 2001
  • In the present study, flow visualizations, hot-wire velocity measurements and computational fluid dynamics were performed in order to determine complicated air flow characteristics in a neonate incubator. In this study, following conclusions can be made: (1) The flow visualization technique developed in the present study revealed an enough qualitative information for the flow field in the neonate incubator. Flow structures in a neonate incubator with a realistic three-dimensional shape was successfully visualized the present study. (2) Results from the flow visualization were relatively in good agreements with those obtained from the computational fluid dynamics. (3) Velocities very near the neonate measured by the hot-wire anemometer were relevant to those obtained from the computational fluid dynamics. (4) Temperatures were higher at the neck region and the medial aspect of both thighs, but lower in both extremities. (5) Small vortices between the neonate and the mattress might interfere with convective and evaporative heat transfers on the neonate's surface. In the fluid dynamic aspect, it is important to eliminate the formation of these small vortices for the design of incubator chamber.

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Slat Noise Source Modeling of Multi-element Airfoil in High-lift Configuration

  • Hwang, Seung Tae;Han, Chang Kyun;Im, Yong Taek;Kim, Jong Rok;Bae, Youngmin;Moon, Young J.
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.2
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    • pp.197-205
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    • 2017
  • We investigate the slat noise generation mechanism by using large-eddy simulation (LES) and simple source modeling based on linearized Euler equations. An incompressible LES of an MD 30P30N three-element airfoil in the high-lift configuration is conducted at $Re_c=1.7{\times}10^6$. Using the total derivative of the hydrodynamic pressure (DP/Dt) acquired from the incompressible LES, representative noise sources in the slat cove region are characterized in terms of simple sources such as frequency-specific monopoles and dipoles. Acoustic radiation around the 30P30N multi-element airfoil is effectively computed using the Brinkman penalization method incorporated with the linearized Euler equation. The directivity pattern of $p^{\prime}_{rms}$ at $r=20c_{slat}$ in the multiple sources is closely compared to that obtained by the application of the LES/Ffowcs-Williams and Hawking's methods to the entire flow field. The power spectrum of p' at ${\theta}=290^{\circ}$ is in good agreement with the data reported in BANC-III, especially the broadband part of the spectrum with a decaying slope ${\propto}f^{-3}$.

A study on an Interface Tracking Algorithm in Friction Stir Welding based on Computational Fluid Dynamics Analysis (전산유체역학을 활용한 마찰교반용접의 해석적 접근에서 표면추적을 위한 알고리즘 연구)

  • Kim, Su-Deok;Na, Suck-Joo
    • Journal of Welding and Joining
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    • v.34 no.3
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    • pp.12-16
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    • 2016
  • Friction stir welding(FSW) was studied using commercial tool, FLOW-3D. The purpose of this study is to suggest a method to apply frictional heat in Computational fluid dynamics(CFD) analysis. Cylindrical tool shape was used, and the interface cells between tool surface and workpiece were tracked by its geometrical relations in order to consider the frictional heat in FSW. After tracking the interface cells, average area concept was used to calculate the frictional heat, which is related to interface area. Also three-dimensional heat source and visco-plastic flow were modeled. The frictional heat generation rate calculated numerically from the suggested algorithm was validated with the analytical solution. The numerical solution was well matched with the analytical solution, and the maximum percentage of error was around 3%.

Applicability of Computational Fluid Dynamics on Industrial Ventilation Engineering (산업환기공학에 대한 전산유체역학의 응용가능성)

  • Ha, Hyun-Chul;Kim, Tae-Hyeung;Shim, Kwang-Jin
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.8 no.2
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    • pp.163-177
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    • 1998
  • Computational Fluid Dynamics(CFD) was applied to predict air flow around the hoods : circular hoods, square hoods, and push-pull hoods. A commercially available CFD software, CFD-ACE(Ver. 4.0), was tested, which is based on the finite volume method using the ${\kappa}-{\varepsilon}$ turbulence model. Numerical results were compared with the experimental, analytical and numerical results from other studies. CFD solutions showed an excellent agreement with the previous experimental and numerical results. It is promising that CFD techniques could be applied on the variety of complex problems in the industrial ventilation engineering.

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The Characteristics Evaluation of the Gas Diffusion Layer for a PEM Fuel Cell by Computational Fluid Dynamics (CFD 해석을 이용한 PEMFC 용 기체확산층의 특성평가)

  • Kim B.H.;Choi J.P.;Jeon B.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.207-210
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    • 2005
  • In this paper, a two-dimensional cross-channel model was applied to investigate influence of the gas diffusion layer(GDL) property and flow field geometry in the anode side for proton exchange membrane fuel cell(PEMFC). The GDL is made of a porous material such as carbon cloth, carbon paper, or metal wire mesh. To the simplicity, the GDL is represented as a block of material containing numerous pathways through which gaseous reactants and liquid water can pass. The purpose of present work was to study the effect of the GDL thickness and the porosity, and flow field geometry by computational fluid dynamics(CFD)

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Weapon Systems for the implementation of an effective Modeling & Simulation on the use of computational fluid dynamics research (무기체계의 효과적인 모델링 및 시뮬레이션 구현을 위한 전산유체역학 활용 연구)

  • Lee, Pil-Jung;Lee, Young-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.8
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    • pp.3492-3496
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    • 2011
  • In Korea Defence in the field of modeling and simulation quite low compared to international levels, and Research & Development and acquisition of weapon systems do not address the reliability in the area is a Free. Thus, in this study using computational fluid dynamics engineering in terms of M & S and the applicability of the present, Future research and development of an effective weapons system acquisition would like to take advantage.