• Title/Summary/Keyword: Lattice Boltzmann

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The Cubic-Interpolated Pseudo-Particle Lattice Boltzmann Advection-Diffusion Model (이류확산 방정식 계산을 위한 입방보간유사입자 격자볼츠만 모델)

  • Mirae, Kim;Binqi, Chen;Kyung Chun, Kim
    • Journal of the Korean Society of Visualization
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    • v.20 no.3
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    • pp.74-85
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    • 2022
  • We propose a Cubic-Interpolated Pseudo-Particle Lattice Boltzmann method (CIP-LBM) for the convection-diffusion equation (CDE) based on the Bhatnagar-Gross-Krook (BGK) scheme equation. The CIP-LBM relies on an accurate numerical lattice equilibrium particle distribution function on the advection term and the use of a splitting technique to solve the Lattice Boltzmann equation. Different schemes of lattice spaces such as D1Q3, D2Q5, and D2Q9 have been used for simulating a variety of problems described by the CDE. All simulations were carried out using the BGK model, although another LB scheme based on a collision term like two-relation time or multi-relaxation time can be easily applied. To show quantitative agreement, the results of the proposed model are compared with an analytical solution.

Stress Based Node Refill Model for Lattice-Boltzmann Method on Fluid-Structure Interaction Problems (격자 볼츠만 법의 유체 구조 연성해석 적용에 대한 응력 기반 격자 재생성 모델)

  • Shin, Jae-Ho;Lee, Sang-Hwan;Lee, Ju-Hee
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.3
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    • pp.12-18
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    • 2012
  • The Lattice Boltzmann Method has developed for solving the Boltzmann equation in Cartesian domains containing immersed boundaries of arbitrary geometrical complexity moving with prescribed kinematics. When a immersed boundaries are sweeping the fixed fluid node, refilling the node information in a vicinity of fluid nodes is one of the important issues in Lattice Boltzmann Method. In this study, we propose a simple refill algorithm for the particle distribution function based on a proper velocity, density and strain rate to enhance accuracy and stability of the method. The refill scheme based on a asymptotic analysis of LBGK model has improved accuracy than interpolation schemes. The proposed scheme in this study is validated by the simulations of an impulsively started rotating circular cylinder to investigate adaptability for fluid-structure interaction (FSI) problem. This refill scheme has improved stability and accuracy especially at high Reynolds number region.

Numerical Simulation of Shock Wave Propagation using the Finite Difference Lattice Boltzmann Method

  • Kang, Ho-Keun;Michihisa Tsutahara;Ro, Ki-Deok;Lee, Young-Ho
    • Journal of Mechanical Science and Technology
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    • v.16 no.10
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    • pp.1327-1335
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    • 2002
  • The shock wave process represents an abrupt change in fluid properties, in which finite variations in pressure, temperature, and density occur over the shock thickness which is comparable to the mean free path of the gas molecules involved. This shock wave fluid phenomenon is simulated by using the finite difference lattice Boltzmann method (FDLBM). In this paper, a new model is proposed using the lattice BGK compressible fluid model in FDLBM for the purpose of speeding up the calculation as well as stabilizing the numerical scheme. The numerical results of the proposed model show good agreement with the theoretical predictions.

Direct Simulation of Acoustic Sound by the Finite Difference Lattice Boltzmann Method (차분격자볼츠만법에 의한 유체음의 직접계산)

  • Kang, Ho-Keun;Ro, Ki-Deok;Lee, Young-Ho
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1827-1832
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    • 2003
  • In this research, the simulation method for acoustic sounds by a uniform flow around a two-dimensional circular cylinder by using the finite difference lattice Boltzmann model is explained. To begin with, we examine the boundary condition which determined with the distribution function $f_i^{(0)}$ concerning with density, velocity and internal energy at boundary node. Very small acoustic pressure fluctuation, with same frequency as that of Karman vortex street, is compared with the pressure fluctuation around a circular cylinder. The acoustic sound' propagation velocity shows that acoustic approa ching the upstream, due to the Doppler effect in the uniform flow, slowly propagated. For the do wnstream, on the other hand, it quickly propagates. It is also apparently the size of sound pressure was proportional to the central distance $r^{-1/2}$ of the circular cylinder. The lattice BGK model for compressible fluids is shown to be one of powerful tool for simulation of gas flows.

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Numerical Simulation of Shock Propatation by the Finite Difference Lattice Boltzmann Method

  • Kang, Ho-Keun;Tsutahara, Michihisa;Kim, Jeong-Hwan;Lee, Young-Ho
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.468-474
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    • 2001
  • The shock process represents an abrupt change in fluid properties, in which finite variations in pressure, temperature, and density occur over a shock thickness which is comparable to the mean tree path of the gas molecules involved. The fluid phenomenon is simulated by using finite difference lattice Boltzmann method (FDLBM). In this research, the new model is proposed using the lattice BGK compressible fluid model in FDLBM for the purpose of shortening in calculation time and stabilizing in simulation operation. The numerical results agree also with the theoretical predictions.

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SIMULATION OF FREE SURFACE FLOW OVER TRAPEZOIDAL OBSTACLE WITH LATTICE BOLTZMANN METHOD (격자볼츠만법을 이용한 장애물 월반 자유수면 시뮬레이션)

  • Korkmaz, Emrah;Jung, Rho-Taek
    • Journal of computational fluids engineering
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    • v.19 no.2
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    • pp.79-85
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    • 2014
  • An air-water free surface flow simulation by using the Lattice Boltzmann Method(LBM) has not been studied a lot compared with the done by the Navier-Stoke equation. This paper shows the LBM is as one of the application tools for the free surface movement over an obstacle. The Mezo scaled application tool has been developed with two dimensional and nine discretized velocity direction using conventional lattice Bhatnagar-Gross-Krook model. Boundary conditions of a halfway-based for solid wall and a kinematic-based for interface are adopted. A validation case with a trapezoidal shape bump to make a comparison between freesurface movements from computational results and experimental ones was described with grid size dependency.

Numerical Simulation of Aerodynamic Sound by the Finite Difference Lattice Boltzmann Method (차분격자볼츠만법에 의한 유동소음의 수치계산)

  • 강호근;김은라
    • Journal of Ocean Engineering and Technology
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    • v.18 no.2
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    • pp.10-17
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    • 2004
  • In this research, a numerical simulation for the acoustic sounds around a two-dimensional circular cylinder in a uniform flaw was developed, using the finite difference lattice Boltzmann model. We examine the boundary condition, which is determined by the distribution function concerning density, velocity, and internal energy at the boundary node. Pressure variation, due to the emission of the acoustic waves, is very small, but we can detect this periodic variation in the region far from the cylinder. Daple-like emission of acoustic waves is seen, and these waves travel with the speed of sound, and are synchronized with the frequency of the lift on the cylinder, due to the Karman vortex street. It is also apparent that the size of the sound pressure is proportional to the central distance to the circular cylinder. The lattice BGK model for compressible fluids is shown to be a powerful tool for the simulation of gas flaws.

Direct Simulation of Edge Tones by the Finite Difference Lattice Boltzmann Method (차분격자볼츠만법에 의한 Edge음의 직접계산)

  • Kang, Ho-Keun;Kim, Yu-Taek;Lee, Young-Ho
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.671-677
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    • 2003
  • Two-dimensional direct numerical simulation of the edge-tones by the finite difference lattice Boltzmann method (FDLBM) is presented. We use a new lattice BGK compressible fluid model that has an additional term and allow larger time increment comparing the conventional FDLBM, and also use a boundary fitted coordinates. We have succeeded in capturing very small pressure fluctuations result from periodically oscillation of jet around the edge. That pressure fluctuations propagate with the sound speed. It is clarified that the sound wave generated in rather wide region and individual vortices do not affect the sound wave propagation.

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NUMERICAL STUDY ON TURBULENT FLOW OVER CYLINDER USING IMMERSED BOUNDARY LATTICE BOLTZMANN METHOD WITH MULTI RELAXATION TIME (다중완화시간 가상경계볼쯔만법을 이용한 실린더 주위의 난류유동해석)

  • Kim, Hyung-Min
    • Journal of computational fluids engineering
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    • v.15 no.2
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    • pp.21-27
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    • 2010
  • Immersed boundary lattice Boltzmann method (IBLBM) has been applied to simulate a turbulent flow over circular cylinder in a flow field effectively. Although IBLBM is very effective method to simulate the flow over a complex shape of obstacle in the flow field regardless of the constructed grids in the calculation domain, the results, however, become numerically unstable in high reynolds number flow. The most effective suggestion to archive the numerical stability in high Reynolds number flow is applying the multiple relaxation time (MRT) model instead of single relaxation time(SRT) model in the collision term of lattice Boltzmann equation. In the research MRT model for IBLBM was introduced and comparing the numerical results obtained by applying SRT and MRT. The hydraulic characteristic of cylinder in a flow field between two parallel plate at the range of $Re{\leqq}2000$represented and it is also compared the drag and lifting coefficients of the cylinder calculated by IBLBM with SRT and MRT model.