A new curved boundary condition in stationary/moving boundaries for the lattice Boltzmann method

Abstract

Lattice Boltzmann method is a new method for fluid flow simulation. Due to its ability for simulation of complex geometry flows, and its properties for parallel programming, this method is considered as an efficient method for fluid flow simulation. Because of curved boundaries in the complex geometries, detecting proper curved boundary condition is unavoidable for the lattice Boltzmann method. For this purpose more works have been done, and different curved boundary conditions were proposed. At the present work, some curved boundary conditions have been reviewed first, and then a new curved boundary condition has been proposed. A computer program based on lattice Boltzmann method, in FORTRAN language, has been prepared, in which proposed boundary condition along with some others, have been applied on it. For verification of accuracy and correctness of the proposed boundary condition, 2D cavity flow has been simulated and compared to available numerical results. Adaptation of achieved results with results of previous researchers, verifies the prepared program correctness. Also, two fluid flows have been simulated, flow around a stationary cylinder in a 2D channel, and flow between two stationary and moving cylinders. Results of simulations with the proposed boundary condition, along with previous boundary conditions, have been compared to available results. Comparisons demonstrate that, solutions with proper accuracy have been obtained by the proposed boundary condition.