• 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 ${\propto}f^{-3}$.

FLUID-STRUCTURE INTERACTION ANALYSIS FOR HIGH ANGLE OF ATTACK MANEUVER MISSILE (고받음각에서 기동하는 미사일의 공력-구조 연계 해석)

  • Noh, K.H.;Park, M.Y.;Park, S.H.;Lee, J.W.;Byun, Y.H.
    • 한국전산유체공학회:학술대회논문집
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    • pp.111-114
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    • 2007
  • Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM) are used to perform aerodynamics analysis and structure analysis. For the fluid-structure interaction analysis, each technology should be considered as well. The process of aerodynamics-structure coupled analysis can be applied to various integrated analyses from many research fields. In this study, the aerodynamics-structure coupled analysis is performed for the missile at high angle of attack condition through the use of Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM). For this purpose, the aerodynamics-structure coupled analyses procedure for the missile are established. The results of the integrated analysis are compared with rigid geometry of the missile and the effect of the deformation will be addressed.

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Computational Fluid Dynamics Modeling Studies on Bacterial Flagellar Motion

  • Kumar, Manickam Siva;Philominathan, Pichai
    • International Journal of Fluid Machinery and Systems
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    • v.4 no.3
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    • pp.341-348
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    • 2011
  • The study of bacterial flagellar swimming motion remains an interesting and challenging research subject in the fields of hydrodynamics and bio-locomotion. This swimming motion is characterized by very low Reynolds numbers, which is unique and time reversible. In particular, the effect of rotation of helical flagella of bacterium on swimming motion requires detailed multi-disciplinary analysis. Clear understanding of such swimming motion will not only be beneficial for biologists but also to engineers interested in developing nanorobots mimicking bacterial swimming. In this paper, computational fluid dynamics (CFD) simulation of a three dimensional single flagellated bacteria has been developed and the fluid flow around the flagellum is investigated. CFD-based modeling studies were conducted to find the variables that affect the forward thrust experienced by the swimming bacterium. It is found that the propulsive force increases with increase in rotational velocity of flagellum and viscosity of surrounding fluid. It is also deduced from the study that the forward force depends on the geometry of helical flagella (directly proportional to square of the helical radius and inversely proportional to pitch).

Computational Fluid Dynamics on The Grid Computing Environment (그리드 컴퓨팅 환경을 이용할 전산 유체 해석)

  • Sung Chun-ho;Cho Kum Won;Park Hyungwoo;Lee Sangsan;Kim Dae-Hee;Kwon Jang Hyuk
    • 한국전산유체공학회:학술대회논문집
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    • pp.71-77
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    • 2002
  • The grid technology is believed to be the next generation research tool for both computational and experimental scientists. With advanced network technologies and middleware, geographically distributed facilities can be tightly connected to provided a huge amount of resources or remote accessibility, In this paper, an overview of grid technology will be introduced with an emphasis in application to computational fluid dynamics. The computational fluid dynamics, which involves solution of partial differential equations, is basically limited by the computing power, With the grid technology, virtually unlimited resources are provided. The schematic structure of middleware and grid environment, as well as some preliminary results are presented.

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