the permeability and tortuosity of pore-scale two and three-dimensional random porous media were calculated using the lattice boltzmann method (lbm). effects of geometrical parameters of medium on permeability and tortuosity were investigated as well. two major models of random porous media were reconstructed by computerized tomography method: randomly distributed rectangular obstacles in a uni...

We propose to stabilize the thermal lattice Boltzmann method by filtering the second- and third-order moments of the collision operator. By means of the Chapman-Enskog expansion, we show that the additional numerical diffusivity diminishes in the low-wavnumber limit. To demonstrate the enhanced stability, we consider a three-dimensional thermal lattice Boltzmann system involving 33 discrete vel...

In this paper, we present a 3D lattice Boltzmann BGK model for simulation of micro ows with heat transfer. This model is an extension of the two-dimensional model that is based on the kinetic theory and the thermal lattice Boltzmann method. The kinetic relations of the relaxation times in this model were linked with the Knudsen number, and a di use scattering boundary condition for the velocity...

In this paper a finite-difference-based lattice Boltzmann method for curvilinear coordinates is proposed in order to improve the computational efficiency and numerical stability of a recent method [R. Mei and W. Shyy, J. Comput. Phys. 143, 426 (1998)] in which the collision term of the Boltzmann Bhatnagar-Gross-Krook equation for discrete velocities is treated implicitly. In the present method,...

This investigation is a three dimensional comprehensive heat transfer analysis for partially differentially heated enclosure with the vertical fin mounted on the hot wall. The thermal lattice Boltzmann based on D3Q19 method is utilized to illustrate the effects of vertical fins and nanoparticles on the flow and thermal fields. The effects of Rayleigh number and different arrangement of fins on ...

in according to the simplicity of the lattice boltzmann method’s(lbm) algorithm and its benefits, it has been used as a successful method in computational fluid dynamics in the last decades. in this paper, lbm was used to simulate the flow over a cylinder. to analyze the application of lbm in simulation curved surface, different methods to compute drag coefficient were used. these methods are: ...