A lattice Boltzmann model is proposed for the double diffusive natural convection system.The flow in a square cavity driven by a temperature gradient and a concentration gradient is then simulated using the present model.The influence of the concentration field on the flow patterns is investigated,and some quantitative comparisons with other studies are made.It is shown that the present LB model can predict the flow characteristics correctly.

A lattice Boltzmann model (LBM) with nonuniform mesh is proposed based on domain decomposition technique.The basic idea is to divide the flow domain into some regular subdomains,and then perform simulations on each subdomain using LBM with uniform mesh.The values on the boundaries of the subdomains are determined by interpolation.The 2-D flow around a cylinder is simulated using the model,the results are also compared with those of other methods.