• Title/Summary/Keyword: ALE(Arbitrary Lagrangian Eulerian) Formulation

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Formulation of Mass Conservation and Linear Momentum Conservation for Saturated Porous Media in Arbitrary Lagrangian Eulerian(ALE) Description (포화된 다공질 매체의 질량 보존과 운동량 보존에 대한 Arbitrary Lagrangian Eulerian(ALE) 정식화)

  • Park, Tae-Hyo;Jung, So-Chan;Kim, Won-Cheul
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.1
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    • pp.5-10
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    • 2003
  • The solids and the fluids in porous media have a relative velocity to each other. Due to physically and chemically different material properties and their relative velocity, the behavior of saturated porous media is extremely complicated. Thus, in order to describe and clarify the deformation behavior of saturated porous media, constitutive models for deformation of porous media coupling several effects need to be developed in frame of Arbitrary Lagrangian Eulerian(ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian elements, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media which are considered for the behavior of the solids and the fluids. For this reason, mass balance equations for saturated porous media are derived here in ALE description frames. ALE formulations of mass conservation for the solid phase and the fluid phase are expressed. Then, linear momentum balance equation for porous media as multiphase media is expressed.

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Computations of Flows and Acoustic Wave Emitted from Moving Body by ALE Formulation in Finite Difference Lattice Boltzmann Model (차분격자볼츠만법에 ALE모델을 적용한 이동물체 주위의 흐름 및 유동소음의 수치모사)

  • KANG HO-KEUN
    • Journal of Ocean Engineering and Technology
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    • v.20 no.1 s.68
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    • pp.48-54
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    • 2006
  • In this paper, flowfield and acoustic-field around moving bodies are simulated by the Arbitrary Lagrangian Eulerian (ALE) formulation in the finite difference lattice Boltzmann method. Some effects are checked by comparing flaw about a square cylinder in ALE formulation and that in the fixed coordinates, and both agree very well. Matching procedure between the moving grid and fixed grid is also considered. The applied method in which the both grids are connected through buffer region is shown to be superior to moving overlapped grid. Dipole-like emissions of sound wave from harmonically vibrating bodies in two- and three-dimensional cases are simulated.

Finite Element Formulation using Arbitrary Lagrangian Eulerian Method for Saturated Porous Media

  • Park, Taehyo;Jung, Sochan
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.375-382
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    • 2003
  • Porous media consist of physically and chemically different materials and have an extremely complicated behavior due to the different material properties of each of its constituents. In addition, the internal structure of porous media has generally a complex geometry that makes the description of its mechanical behavior quite complex. Thus, in order to describe and clarify the deformation behavior of porous media, constitutive models for deformation of porous media coupling several effects such as flow of fluids of thermodynamical change need to be developed in frame of Arbitrary Lagrangian Eulerian (ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian methods, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media that are considered for the behavior of solids and fluids. First of all, governing equations for saturated porous media based on ALE description are derived. Then, weak forms of these equations are obtained in order to implement numerical method using finite element method. Finally, Petrov-Galerkin method Is applied to develop finite element formulation.

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An ALE Finite Element Formulation for Rigid-Viscoplatic Materials and Its Application to Axisymmetric Extrusion through Square Dies (ALE 묘사에 근거한 강-점소성 유한요소 수식화와 축대칭 평금형 압출에의 적용)

  • 강연식;양동열
    • Transactions of Materials Processing
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    • v.3 no.2
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    • pp.156-166
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    • 1994
  • An arbitrary Lagrangian-Eulerian (ALE) finite element method has been developed. The finite element formation is derived and implemented for rigid-viscoplastic materials. The developed computer program is applied to the analysis of axisymmetric square die extrusion, which has many difficulties with updated Lagrangian approach. The results are compared with those from updated Largrangian approach. The results are compared with those from updated Lagrangian finite element program. Updating scheme of time dependent variables and mesh control are also examined.

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Direct Simulation of Flows and Flow Noise around Moving Body by FDLBM with ALE Model (ALE모델을 갖는 차분격자볼츠만법에 의한 이동물체 주위의 유동장 및 유동소음의 직접계산)

  • Kang, Ho-Keun;Michihisa, Tsutahara;Kim, Myoung-Ho;Kim, Yu-Taek;Lee, Young-Ho
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.248-249
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    • 2005
  • In this paper, flowfield and acoustic-field around moving bodies are simulated by the Arbitrary Lagrangian Eulerian (ALE) formulation in FDLBM. The effect of the ALE is checked by comparing flow about a square cylinder in ALE formulation and that in the fixed coordinates, and the results show good agreement. Matching procedure between the moving grid and fixed grid is also considered. The applied method in which the both grids are connected through buffer zone is shown to be superior to moving overlapped grid. Dipole-like emissions of sound wave from harmonically vibrating bodies in 2- and 3-dimensional cases are simulated.

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A Three-Dimensional Rigid-Viscoplastic Finite Element Analysis of isothermal Square Die Extrusion of a Square Section Based on ALE Description (강-점소성 ALE 유한요소 수식화에 근거한 사각형 형재의 평금형 등온 압출에 대한 3차원 해석)

  • 강연식;양동열
    • Transactions of Materials Processing
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    • v.5 no.1
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    • pp.55-60
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    • 1996
  • In the finite element analysis of metal forming processes the updated Lagrangian approach has been widely and effectively used to simulate the non-steady state problems. however some difficulties have arisen from abrupt flow change as in extrusion through square dies. In the present work an ALE(arbitrary Lagrangian-Euleria) finite element formulation for deforma-tion analysis are presented fro rigid-viscoplastic materials. The developed finite element program is applied to the isothermal analysis of square die extrusion of a square section. The computational results are compared with those by the updated Lagrangian finite element analysis.

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An ALE Finite Element Method for Baffled Fuel Container in Yawing Motion

  • Cho, Jin-Rae;Lee, Hong-Woo;Yoo, Wan-Suk;Kim, Min-Jeong
    • Journal of Mechanical Science and Technology
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    • v.18 no.3
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    • pp.460-470
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    • 2004
  • A computational analysis of engineering problems with moving domain or/and boundary according to either Lagrangian or Eulerian approach may encounter inherent numerical difficulties, the extreme mesh distortion in the former and the material boundary indistinctness in the latter. In order to overcome such defects in classical numerical approaches, the ALE(arbitrary Lagrangian Eulerian) method is widely being adopted in which the finite element mesh moves with arbitrary velocity. This paper is concerned with the ALE finite element formulation, aiming at the dynamic response analysis of baffled fuel-storage container in yawing motion, for which the coupled time integration scheme, the remeshing and smoothing algorithm and the mesh velocity determination are addressed. Numerical simulation illustrating theoretical works is also presented.

A Study on the Slipping Problem for Cable-Membrane Structures (케이블-막구조물의 요소이동(slip)에 관한 연구)

  • Kim, Jae-Yeol;Kang, Joo-Won;Park, Sang-Min
    • Journal of Korean Association for Spatial Structures
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    • v.8 no.5
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    • pp.95-105
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    • 2008
  • The objective of this study is find out the stressed condition, slipped direction and slipped dimension when some elements of cable-membrane structures are slipped from it's initially designed coordinates by external loads as wind or non uniform load and so on. In order to search the slipped behaviors of cable-membrane structures, a ALE finite element formulation is introduced. In these procedures, a stiffness matrix related with ALE concept is formulated and a FE analysis program for cable-membrane structures with slipped elements is developed.

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Simulation of dynamic fracture and fluid-structure interaction in solid propellant rockets : Part 1 (theoretical aspects) (고체추진로켓 내부에서 발생하는 동적 파괴 현상과 유체-고체 상호작용의 시뮬레이션 - Part 1 (이론적 측면))

  • Hwang, Chan-Gyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.2
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    • pp.286-290
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    • 2008
  • This paper summarizes the components of an explicit aeroelastic solver developed especially for the simulation of dynamic fracture events occurring during the flight of solid propellant rockets. The numerical method combines an explicit Arbitrary Lagrangian Eulerian (ALE) version of the Cohesive Volumetric Finite Element (CVFE) scheme, used to simulate the spontaneous motion of one or more cracks propagating dynamically through a domain with regressing boundaries, and an explicit unstructured finite volume Euler code to follow the flow field during the failure event. A key feature of the algorithm is the ability to adaptively repair and expand the fluid mesh to handle the large geometrical changes associated with grain deformation and crack motion.

Estimation of Acceleration Response of Freefall Lifeboat using FSI Analysis Technique of LS-DYNA Code (LS-DYNA 코드의 유체-구조 연성해석 기법을 이용한 자유낙하식 구명정의 가속도 응답 추정)

  • Bae, Dong-Myung;Zakki, A.F.;Kim, Hag-Soo;Kim, Joo-Gon
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.5
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    • pp.681-688
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    • 2010
  • During certification of freefall lifeboats, it is necessary to estimate the injury potential of the impact loads exerted on the occupants during water entry. This paper focused on the numerical simulation to predict the acceleration response during the impact of freefall lifeboats on the water using FSI(Fluid-Structure Interaction) analysis technique of LS-DYNA code. FSI problems could be conveniently simulated by the overlapping capability using Arbitrary Lagrangian Eulerian(ALE) formulation and Euler-Lagrange coupling algorithm of LS-DYNA code. Through this study, it could be found that simulation results were in relatively good agreement with experimental ones in the acceleration peak values, and that the loading conditions were very sensitive to the acceleration responses by the experimental and simulation results.