Parallelization of lattice Boltzmann method for incompressible flow computations

Parallel computation of the two and three-dimensional decaying homogeneous isotropic turbulence using the lattice Boltzmann method are presented. BGK type approximation for collision term in 9 velocity square lattice model is used. It is found that the lattice Boltzmann method is able to reproduce the dynamics of decaying turbulence and could be an alternative for solving the Navier-Stokes equations. The lattice Boltzmann method is parallelized by using domain decomposition and implemented on a distributed memory computer, Hitachi SR2201. It is found that vertical decomposition gives the highest speedup. In the case of horizontal decomposition the longer the number of lattice units in horizontal direction of each subdomain, the shorter the CPU time. Extension to three-dimension is carried out using 15 velocity cubic lattice model. Compared with the result of two-dimensional case, a higher speedup is obtained than in the three-dimensional simulation. Further investigation is needed on the accuracy and efficiency of cubic lattice BGK model.