A bubble(droplet) collides with a bubble(droplet) at a large relative velocity. The transition behavior during collision is different from the low speed case in Fig. 7. The parameters are λ 1 = λ 3 = − 1.4 , λ 2 = λ 4 = 2.4 , k 1 = k 2 = 1 , c 1 = c 2 = 3 , and α 1 = α 4 = − 3 , α 2 = α 3 = 3 .