• Title/Summary/Keyword: Free surface capturing

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A Study on a VOF Method for the Improvement of Free Surface Capturing (VOF 법의 자유수면 포착정도 향상을 위한 연구)

  • Park, Il-Ryong;Kim, Wu-Joan;Kim, Jin;Van, Suak-Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.2 s.140
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    • pp.88-97
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    • 2005
  • A new numerical scheme solving two-phase flow, the Hybrid VOF method for improved free surface capturing has been developed by combining a volume capturing VOF method with the Level-Set reinitialization procedure. For validation, the proposed method is applied to 3-D bubble rising problem, dam breaking and the free surface flow around a commercial container ship. The calculated results by using the Hybrid VOF method with the two previously applied VOF formulations are compared with available numerical and experimental data. It is found that the new method provides more reasonable results than the two previous ones.

VOLUME CAPTURING METHOD USING UNSTRUCTURED GRID SYSTEM FOR NUMERICAL ANALYSIS OF MULTIPHASE FLOWS (다상유동 해석을 위한 비정렬격자계를 사용한 체적포착법)

  • Myong, H.K.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.11a
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    • pp.201-210
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    • 2009
  • A volume capturing method using unstructured grid system for numerical analysis of multiphase flows is introduced in the present paper. This method uses an interface capturing method (CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The novelty of CICSAM lies in the adaptive combination of high resolution discretization scheme which ensures the preservation of the sharpness and shape of the interface while retaining boundedness of the field, and no explicit interface reconstruction which is perceived to be difficult to implement on unstructured grid system. Several typical test cases for multiphase flows are presented, which are simulated by an in-house solution code(PowerCFD). This code employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with CICSAM. It is found that the present method simulates efficiently and accurately complex free surface flows such as multiphase flows.

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Computation of Two-Fluid Flows with Submerged hydrofoil by Interface Capturing Method (접면포착법에 의한 수중익 주위의 이층류 유동계산)

  • 곽승현
    • Journal of Korean Port Research
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    • v.13 no.1
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    • pp.167-174
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    • 1999
  • Numerical analysis of two-fluid flows for both water and air is carried out. Free-Surface flows with an arbitrary deformation have been simulated around two dimensional submerged hydrofoil. The computation is performed using a finite volume method with unstructured meshes and an interface capturing scheme to determine the shape of the free surface. The method uses control volumes with an arbitrary number of faces and allows cell-wise local mesh refinement. the integration in space is of second order based on midpoint rule integration and linear interpolation. The method is fully implicit and uses quadratic interpolation in time through three time levels The linear equation systems are solved by conjugate gradient type solvers and the non-linearity of equations is accounted for through picard iterations. The solution method is of pressure-correction type and solves sequentially the linearized momentum equations the continuity equation the conservation equation of one species and the equations or two turbulence quantities.

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A STUDY ON AN INTERFACE CAPTURING METHOD APPLICABLE TO UNSTRUCTURED MESHES FOR THE ANALYSIS OF FREE SURFACE FLOW (자유표면유동 해석을 위한 비정렬격자계에 적합한 경계면포착법 연구)

  • Myong, H.K.;Kim, J.E.
    • Journal of computational fluids engineering
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    • v.11 no.4 s.35
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    • pp.14-19
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    • 2006
  • A conservative finite-volume method for computing 3-D flow with an unstructured cell-centered method has been extended to free surface flows or two-fluid systems with topologically complex interfaces. It is accomplished by implementing the high resolution method(CICSAM) by Ubbink(1997) for the accurate capturing of fluid interfaces on unstructured meshes, which is based on the finite-volume technique and is fully conservative. The calculated results with the present method are compared to show the ease and accuracy with available numerical and experimental results reported in the literature.

Numerical Analysis of Violent Sloshing Problems by CCUP Method (CCUP 기법을 이용한 2 차원 슬로싱 문제의 수치해석)

  • Yang, Kyung-Kyu;Kim, Yong-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.1
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    • pp.1-10
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    • 2010
  • In the present paper, a numerical method based on the constraint interpolation profile (CIP) method is applied for simulating two-dimensional violent sloshing problems. The free surface boundary value problem is considered as a multiphase problem which includes water and air. A stationary Cartesian grid system is adopted, and an interface capturing method is used to trace the shape of free surface profile. The CIP combined unified procedure (CCUP) scheme is applied for flow solver, and the tangent of hyperbola for interface capturing (THINC) scheme is used for interface capturing. Numerical simulations have been carried out for partially-filled 2D tanks under forced sway and roll motions at various filling depths and frequencies. The computational results are compared with experiments and/or the other numerical results to validate the present numerical method.

Computation of Water and Air Flow with Submerged Hydrofoil by Interface Capturing Method

  • Kwag, Seung-Hyun
    • Journal of Mechanical Science and Technology
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    • v.14 no.7
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    • pp.789-795
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    • 2000
  • Free-surface flows with an arbitrary deformation, induced by a submerged hydrofoil, are simulated numerically, considering two-fluid flows of both water and air. The computation is performed by a finite volume method using unstructured meshes and an interface capturing scheme to determine the shape of the free surface. The method uses control volumes with an arbitrary number of faces and allows cell wise local mesh refinement. The integration in space is of second order, based on midpoint rule integration and linear interpolation. The method is fully implicit and uses quadratic interpolation in time through three time levels. The linear equations are solved by conjugate gradient type solvers, and the non-linearity of equations is accounted for through Picard iterations. The solution method is of pressure-correction type and solves sequentially the linearized momentum equations, the continuity equation, the conservation equation of one species, and the equations for two turbulence quantities. Finally, a comparison is quantitatively made at the same speed between the computation and experiment in which the grid sensitivity is numerically checked.

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Numerical Simulation of Multiphase Flows with Material Interface due to Density Difference by Interface Capturing Method (경계면 포착법에 의한 밀도차이에 따른 물질경계면을 갖는 다상유동 수치해석)

  • Myon, Hyon-Kook
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.6
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    • pp.443-453
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    • 2009
  • The Rayleigh-Taylor instability, the bubble rising in both partially and fully filled containers and the droplet splash are simulated by an in-house solution code(PowerCFD), which are typical benchmark problems among multiphase flows with material interface due to density difference. The present method(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 method simulates efficiently and accurately complex free surface flows such as multiphase flows with material interface due to both density difference and instability.

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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A Study on a VOF Method for Improved Free Surface Capturing (VOF법의 자유수면 포착정도 향상을 위한 연구)

  • Park Il-Ryong;Kim Wu-Joan;Kim Jin;Van Suak-Ho
    • 한국전산유체공학회:학술대회논문집
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    • 2005.04a
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    • pp.202-206
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    • 2005
  • A new numerical scheme for two-phase flows, the Hybrid VOF method has been developed for improved free surface capturing. The present new method is a volume capturing based VOF method coupled with a reinitialization procedure of a Level-set method. For validation, the proposed method is applied to two test cases: spherical bubble rising and dam breaking. The calculated results by using the Hybrid VOF method with the two previously applied VOF formulations are compared with available numerical and experimental data. It is found that the new method provides more accurate results than the two previous ones.

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Numerical Simulation of Two-Dimensional Multiphase Flows due to Density Difference by Interface Capturing Method (경계면포착법에 의한 밀도차에 따른 다상유동 수치해석)

  • Myong, Hyon-Kook
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.572-575
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    • 2008
  • Two-dimensional multiphase flows due to density difference such as the Rayleigh-Taylor instability problem and the droplet splash are simulated by an in-house solution code(PowerCFD). This code employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method 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 simulates complex free surface flows such as multiphase flows due to density difference efficiently and accurately.

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