Numerical simulation of bubble flows by the lattice Boltzmann method

A lattice Boltzmann method for two-phase immiscible fluids with large density ratios is proposed. The difficulty in the treatment of large density ratio is resolved by using the projection method. The method can simulate two-phase fluid flows with the density ratio up to 1000. The method is applied to the simulations of a single rising bubble in liquid and many bubbles rising in a square duct. The terminal shapes and the terminal Reynolds numbers of the single bubble for various Morton and Eotvos numbers are in good agreement with available experimental data. The complicated unsteady structures of the interface and the flow field are illustrated in many bubbles rising in a square duct.