Chih-Fung Ho¹, Cheng Chang¹, Kuen-Hau Lin¹, Chao-An Lin^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.44, No.2, pp. 137-156, 2009, DOI:10.3970/cmes.2009.044.137

Abstract Consistent formulations of 2D and 3D pressure and velocity boundary conditions along both the stationary and non-stationary plane wall and corner for lattice Boltzmann simulations are proposed. The unknown distribution functions are made function of local known distribution functions and correctors, where the correctors at the boundary nodes are obtained directly from the definitions of density and momentum. This boundary condition can be easily implemented on the wall and corner boundary using the same formulation. Discrete macroscopic equation is also derived for steady fully developed channel flow to assess the effect of the boundary condition… More >

Ahmed Mezrhab¹, Hassan Naji²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 283-296, 2009, DOI:10.3970/fdmp.2009.005.283

Abstract The objective of this paper is to assess the effectiveness of the coupled Lattice Boltzmann Equation (LBE) and finite volume method strategy for the simulation of the interaction between thermal radiation and laminar natural convection in a differentially heated square cavity. The vertical walls of the cavity are adiabatic, while its top and bottom walls are cold and hot, respectively. The air velocity is determined by the lattice Boltzmann equation and the energy equation is discretized by using a finite volume method. The resulting systems of discretized equations have been solved by an iterative procedure More >

R. Djebali^1,2, M. El Ganaoui^2,3, H. Sammouda¹, R. Bennacer⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.3, pp. 261-282, 2009, DOI:10.3970/fdmp.2009.005.261

Abstract The simplified thermal lattice Boltzmann model (STLBM) developed by Peng, Shu and Chew (2003) is used in this work to simulate low-Rayleigh-number natural convection in a heated rectangular cavity on a uniform grid. It is shown how by resorting to the double populations approach both hydrodynamic and thermal fields can be effectively simulated. Furthermore, a general benchmark is carried out to account for the effect of different parameters in relatively wide ranges. Results are compared with previous works available in the literature. More >

M.R. Arab^1,2, E. Semma³, B. Pateyron¹, M. El Ganaoui¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.2, pp. 161-176, 2009, DOI:10.3970/fdmp.2009.005.161

Abstract In this work, flows in porous media are simulated by using a Lattice Boltzmann Method (LBM). A model D2Q9 with a single collision operator is proposed. This method is applied on 2D digital images obtained by a Scanning Electron Microscope technique (SEM), and followed by a special treatment in order to obtain an image of synthesis that is finally read by the numerical code. The first results tested on two-dimensional configurations show the reliability of this strategy in simulating with a good accuracy phenomena of heat and mass transport. The numerical study is extended to More >

Cheng-Hsiu Yang¹, Cheng Chang¹, Chao-An Lin^1,2

CMC-Computers, Materials & Continua, Vol.11, No.3, pp. 209-228, 2009, DOI:10.3970/cmc.2009.011.209

Abstract In the present study, a lattice Boltzmann method based new immersed boundary technique is proposed for simulating two-dimensional viscous incompressible flows interacting with stationary and moving solid boundaries. The lattice Boltzmann method with known force field is used to simulate the flow where the complex geometry is immersed inside the computational domain. This is achieved via direct-momentum forcing on a Cartesian grid by combining "solid-body forcing" at solid nodes and interpolation on neighboring fluid nodes. The proposed method is examined by simulating decaying vortex, 2D flow over an asymmetrically placed cylinder, and in-line oscillating cylinder More >

B.K. Raghu Prasad¹, T.V.R.L. Rao¹, A.R.Gopalakrishnan¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 99-112, 2008, DOI:10.3970/icces.2008.006.099

Abstract A modified lattice model using finite element method has been developed to study the mode-I fracture analysis of heterogeneous materials like concrete. In this model, the truss members always join at points where aggregates are located which are modeled as plane stress triangular elements. The truss members are given the properties of cement mortar matrix randomly, so as to represent the randomness of strength in concrete. It is widely accepted that the fracture of concrete structures should not be based on strength criterion alone, but should be coupled with energy criterion. Here, by incorporating the More >

Shih-Kai Chien¹, Tzu-Hsiang Yen¹, Yue-Tzu Yang¹, Chao-Kuang Chen^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.3, pp. 163-174, 2008, DOI:10.3970/cmes.2008.029.163

Abstract Conventional proton exchange membrane fuel cells (PEMFCs) have a straight gas flow serpentine channel, and hence the reactant gases are transferred to the catalyst layers as a result of diffusion alone. Since the diffusion process is inherently slow, the electrical performance of such PEMFCs is inevitably limited. In an attempt to improve the PEMFC performance, this study replaces the straight channel with containing different type of obstacles and conducts a series of lattice Boltzmann method simulations to investigate the flow field phenomena induced in a viscous liquid as it flows along the serpentine channel at… More >

E. Pan^1,2, Y. Zhang², P. W. Chung³, M. Denda⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.24, No.2&3, pp. 157-168, 2008, DOI:10.3970/cmes.2008.024.157

Abstract Quantum-dot (QD) semiconductor synthesis is one of the most actively investigated fields in strain energy band engineering. The induced strain fields influence ordering and alignment, and the subsequent surface formations determine the energy bandgap of the device. The effect of the strains on the surface formations is computationally expensive to simulate, thus analytical solutions to the QD-induced strain fields are very appealing and useful. In this paper we present an analytical method for calculating the QD-induced elastic field in anisotropic half-space semiconductor substrates. The QD is assumed to be of any polyhedral shape, and its… More >

Cha’o-Kuang Chen¹, Shing-Cheng Chang¹, Szu-Yu Sun¹

CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 203-216, 2007, DOI:10.3970/cmes.2007.022.203

Abstract In this study, the channel flow is discussed by the LBM simulations. In the cases of channel with obstacles inside, the square pillars play the role of causing interruption within the fluid field, and hence change the direction of fluid flow. The recirculation region is formed behind the obstacles and influences the fluid passed through not only in the velocity field but also in the temperature field. Therefore, heat transfer is enhanced in local region.
The field synergy principle is applied in the research to demonstrate that the increased interruption within the fluid increases the More >

K. Han ¹, Y. T. Feng ¹, D. R. J. Owen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.2, pp. 87-100, 2007, DOI:10.3970/cmes.2007.018.087

Abstract Numerical procedures are introduced for simulations of irregular particle transport in turbulent flows using the coupled lattice Boltzmann method (LBM) and the discrete element method (DEM). The fluid field is solved by the extended LBM with the incorporation of the Smagorinsky turbulence approach, while particle interaction is modeled by the DEM. The hydrodynamic interactions between fluid and particles are realised through an immersed boundary condition, which gives rise to a coupled solution strategy to model the fluid-particle system under consideration. Main computational aspects comprise the lattice Boltzmann formulation for the solution of fluid flows; the More >