• Title/Summary/Keyword: Volume Of fluids method

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NAVIER-STOKES SIMULATION OF A MICRO-VISCOUS PUMP (초소형 점성 펌프의 Wavier-Stokes 해석)

  • Kang, D.J.
    • Journal of computational fluids engineering
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    • v.11 no.4 s.35
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    • pp.75-80
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    • 2006
  • Navier-Stokes simulation of the flow in a micro viscous pump is carried out. The micro viscous pump consists of a rotating circular rotor placed in a two dimensional channel. All simulation is carried out by using a finite volume approach, at the Reynolds number of 0.5, to study the performance of the micro viscous pump. Length of channel of the pump is varied to simulate the effects of the pumping load. Numerical solutions show that the net flow of the pump is realized by two counter rotating vortices formed on both sides of the rotor. The volume flow rate of the pump is decreased as length of the channel is increased, while the static pressure difference across the rotor is increased. The static pressure difference across the rotor is observed to be inversely proportional to the volume flow rate as inertia effects are negligibly small. The efficiency of the pump is found to reach a maximum when two counter rotating vortices on both sides of the rotor becomes to merge forming an outer enveloping vortex.

Numerical analysis of submerged jet by VOF method (VOF법을 이용한 수중 제트의 수치해석)

  • Park G. H.;Kim H. J.;Kwon S. J.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.178-182
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    • 2004
  • Numerical analysis of a gaseous jet submerged in a liquid environment was carried out using the volume of fluid(VOF) method to simulate the kinematics of the gas-liquid interface. Two nozzle geometries were tested, one for Fanno tube and the other for converging diverging nozzle. Commercial code was used for the present calculation. Transient behavior of a gaseous jet since its start showed periodic nature of the jet, which was also observed in previous measurements.

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A NUMERICAL SIMULATION OF INFRARED RADIATION OF EXHAUST PLUME (배기 후류의 적외선 방사 특성 모사를 위한 수치적 연구)

  • Zhang, Y.;Yang, Y.R.;Park, G.R.;Myong, R.S.;Cho, T.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.422-425
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    • 2010
  • The infrared radiation of exhaust plume was investigated numerically by a finite volume method (FVM) with anisotropic scattering particles. The exhaust plume is considered to absorb, emit and scatter radiant energy isotropically as well as anisotropically. The spatial and spectral distribution characteristics were obtained for the detection wavelength with $2.7{\mu}m$. The radiative intensities were presented for the different detective direction.

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The Interaction of Vortex and Premixed Flame with Consideration of Volume Expansion Effect (체적팽창효과를 고려한 예혼합화염과 와동의 상호작용에 관한 연구)

  • Jeong Ui-Heon;Gwon Se-Jin
    • 한국전산유체공학회:학술대회논문집
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    • 1998.11a
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    • pp.204-210
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    • 1998
  • A method is developed to include the effect of volume expansion in the description of the flame dynamics using G-equation. Line volume-source is used to represent the effect of the exothermic process of combustion with source strength determined by the density difference between the burned and the unburned region. Volume expansion adjusts the flow field to accommodate the increased volume flow rate crossing the flame front. Test result predicted the measured velocity field qualitatively. The method was applied to study the interaction of vortex and premixed flame. Increased volume expansion did not change the initial growth rate of flame area. However, the residence time and flame surface area increased with higher expansion ratios.

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A COMPARATIVE STUDY BETWEEN DISCONTINUOUS GALERKIN AND SPECTRAL VOLUME METHODS ON STRUCTURED GRIDS (2차원 정렬 격자계에서의 불연속 갤러킨 기법과 Spectral Volume 기법 비교 연구)

  • Koo H. S.;Kim K. H.;Kim C. A.
    • 한국전산유체공학회:학술대회논문집
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    • 2005.10a
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    • pp.131-134
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    • 2005
  • Conventional high order interpolation schemes are limitative in several aspects mainly because they need data of neighboring cells at the reconstruction step. However, discontinuous Galerkin method and spectral volume method, two high order flux schemes which will be analyzed and compared in this paper, have an important benefit that they are not necessary to determine the flow gradients from data of neighboring cells or elements. These two schemes construct polynomial of variables within a cell so that even near wall or discontinuity, the high order does not deteriorate.

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Numerical Analysis for the Piston-Driven Intake Flows using the Finite Element Method (피스톤에 의해 유입되는 유동에 대한 유한요소법을 이용한 수치해석)

  • Choi J. W.;Park C. K.
    • Journal of computational fluids engineering
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    • v.4 no.2
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    • pp.39-46
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    • 1999
  • The FVM(Finite Volume Method) have been used mainly for the flow analyses in the piston-cylinder. The objective of the present study is to analyze numerically the piston-driven intake flows using the FEM(Finite Element Method). The FEM algorithm used in this study is 4-step time-splitting method which requires much less execution time and computer storage than the velocity-pressure integrated method and the penalty method. And the explicit Lax-Wendroff scheme is applied to nonlinear convective term in the momentum equations to prevent checkerboard pressure oscillations. Also, the ALE(arbitrary Lagrangian Eulerian) method is adopted for the moving grids. The calculated results show good agreement in comparison with those by the FVM and the experimental results by the LDA.

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NUMERICAL SIMULATION OF FLOWS INDUCED BY WALL ADHESION (벽면흡착에 의해 야기되는 유동 수치해석)

  • Myong, H.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.2-5
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    • 2011
  • This paper presents a numerical study on multiphase flows induced by wall adhesion The CSF(Continuum Surface Force} model is used for the calculation of the surface tension force and implemented in an in-house solution code(PowerCFD). The present method(code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with volume capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing As an application of the present method, the effects of wall adhesion are numerically simulated with the CSF model for a shallow pool of water located at the bottom of a cylindrical tank. Two different cases are computed, one in which the water wets the wall and one in which the water does not wet the wall. It is found that the present method simulates efficiently and accurately surface tension-dominant multiphase flows induced by wall adhesion.

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NUMERICAL STUDY ON TWO-DIMENSIONAL MULTIPHASE FLOWS DUE TO DENSITY DIFFERENCE WITH INTERFACE CAPTURING METHOD (경계면 포착법을 사용한 밀도차에 따른 다상유동에 관한 수치해석적 연구)

  • Myong, H.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.214-219
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    • 2007
  • Both the bubble rising in a fully filled container and the droplet splash are simulated by a solution code(PowerCFD). This code employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method (CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The present results are compared with other numerical solutions found in the literature. It is found that the present code simulate complex free surface flows such as multi phase flows due to large density difference efficiently and accurately.

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Real-time Flow Animation Techniques Using Computational Fluid Dynamics (전산유체역학을 이용한 실시간 유체 애니메이션 기술)

  • Kang Moon Koo
    • Journal of the Korean Society of Visualization
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    • v.2 no.2
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    • pp.8-15
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    • 2004
  • With all the recent progresses in computer hardware and software technology, the animation of fluids in real-time is still among the most challenging issues of computer graphics. The fluid animation is carried out in two steps - the physical simulation of fluids immediately followed by the visual rendering. The physical simulation is usually accomplished by numerical methods utilizing the particle dynamics equations as well as the fluid mechanics based on the Navier-Stokes equations. Particle dynamics method is usually fast in calculation, but the resulting fluid motion is conditionally unrealistic. The methods using Navier-Stokes equation, on the contrary, yield lifelike fluid motion when properly conditioned, yet the complexity of calculation restrains this method from being used in real-time applications. This article presents a rapid fluid animation method by using the continuum-based fluid mechanics and the enhanced particle dynamics equations. For real-time rendering, pre-integrated volume rendering technique was employed. The proposed method can create realistic fluid effects that can interact with the viewer in action, to be used in computer games, performances, installation arts, virtual reality and many similar multimedia applications.

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