• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1768-1772
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• 2010

Intra-molecular association is an important contribution to the overall hydrogen bonding in surfactant systems, especially in systems of colloidal and biological interest. Amphiphile systems, especially micelle and microemulsion systems, showed highly non-ideal behavior due to the intermolecular association and intra-molecular association. The objective of this research is to present a lattice fluid equation of state that combines the quasi-chemical nonrandom lattice fluid model with modified Veytsman statistics for intra + inter molecular association to calculate phase behavior for mixture containing surfactant systems. The lattice model could describe the literature data well for alkane and surfactant systems.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.225-235
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• 2009

Lattice process models are used to explain phase transitions in statistical mechanics, a branch of physics. The Ising model, a specific form of lattice process model, was proposed by Ising in 1925. Since then, variants of the Ising model such as the Potts model and the unitary cell model have been proposed. Like the Ising model, it is believed that the more general models exhibit phase transitions on the critical surface, which is based on the mathematical equation. In statistical sense, phase transitions can be simulated through Markov Chain Monte Carlo (MCMC). We applied Swendsen-Wang algorithm, a block Gibbs algorithm, to a general lattice process models and we simulate phase transition phenomena of the unitary cell model.

• Coupled systems mechanics
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• v.7 no.1
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• pp.27-42
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• 2018

Behavior of soil is usually described with continuum type of failure models such as Mohr-Coulomb or Drucker-Prager model. The main advantage of these models is in a relatively simple and efficient way of predicting the main tendencies and overall behavior of soil in failure analysis of interest for engineering practice. However, the main shortcoming of these models is that they are not able to capture post-peak behavior of soil nor the corresponding failure modes under extreme loading. In this paper we will significantly improve on this state-of-the-art. In particular, we propose the use of a discrete beam lattice model to provide a sharp prediction of inelastic response and failure mechanisms in coupled soil-foundation systems. In the discrete beam lattice model used in this paper, soil is meshed with one-dimensional Timoshenko beam finite elements with embedded strong discontinuities in axial and transverse direction capable of representing crack propagation in mode I and mode II. Mode I relates to crack opening, and mode II relates to crack sliding. To take into account material heterogeneities, we determine fracture limits for each Timoshenko beam with Gaussian random distribution. We compare the results obtained using the discrete beam lattice model against those obtained using the modified three-surface elasto-plastic cap model.

• Applied Microscopy
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• v.45 no.4
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• pp.230-235
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• 2015

Crystallographic models are effective tools to interpret, calculate and even to predict the preferred crystallographic morphologies of precipitates in various precipitation systems. The present study gives an introduction on the recently developed secondary constrained coincident site lattice (II-CCSL) model. Using the II-CCSL model, the interface matching condition of the ${\beta}-Mg_{17}Al_{12}$ precipitates with ${\alpha}-Mg$ matrix in an aged AZ91 alloy has been analyzed to rationalize the morphologies of the precipitates. The results show that the characteristic crystallographic features of the observed ${\beta}-Mg_{17}Al_{12}$ precipitates, i.e., the habit plane of the ${\beta}-Mg_{17}Al_{12}$ lath with a Burgers orientation relationship (OR) and the growth direction of the ${\beta}-Mg_{17}Al_{12}$ with a Crawley OR exhibit a better lattice matching degree than their vicinal orientations. Moreover, the Crawley OR is preferred to the Burgers OR due to a better lattice match.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.248-252
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• 2004

The mechanical properties of polycrystalline thin-films, critical for Micro-Electro-Mechanical Systems (MEMS) components, are known to have the size effect and the scatter in the length scale of microns by the numbers of intensive investigation by experiments and simulations. So, the consideration of the microstructure is essential to cover these length scale effects. The lattice based stochastic model for the microstructure evolution is used to simulate the actual microstructure, and the fast and reliable algorithm is described in this paper. The kinetics parameters, which are the key parameters for the microstructure evolution based on the nucleation and growth mechanism, are extracted from the given micrograph of a polycrystalline material by an inverse method. And the method is verified by the comparison of the quantitative measures, the number of grains and the grain size distribution, for the actual and simulated microstructures. Finite element mesh is then generated on this lattice based microstructure by the developed code. And the statistical finite element analysis is accomplished for selected microstructure.

• 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.

• 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.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.407-410
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• 2006

This study describes a simulation of two-dimensional bubble forming and motion by the Lattice Boltzmann Method with the phase field equation. The free energy model is used to treat the interfacial force and deformation of binary fluids system, drawn into a T-junction the micro channel. A numerical simulation of a binary flow in a cross-junction channel is carried out by using the parallel computation method. The aim in this investigation is to examine the applicability of LBM to numerical analysis of binary fluid separation and motion in the micro channel.

• 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.