Multiple bubbles rising and interaction in a quiescent viscous incompressible fluid was simulated with three-dimensional lattice Boltzmann free energy model with a large density ratio.In order to avoid numerical instability caused by a large density ratio

eight-point and eighteen-point difference schemes were used to calculate the first and the second order derivative 1586Φ and 15862Φ

respectively.The results of simulation presented the effects of initial bubble size and location on the flow field induced by rising bubbles and on the evolution of bubble shape.For multiple rising bubbles with the same size

the trailing bubble was influenced by the wake of the leading bubble.The strength of influence depended on both the distance between bubbles and the relative position.With the increase of distance

the strength decreased gradually.For multiple bubbles with different sizes

however

the larger bubble always strongly affected the smaller one at any initial size and location.