The dynamics of twin and triple nucleation sites interaction has been investigated. Nonlinear data analysis techniques such as the dimension spectrum and largest Lyapunov exponent have been used for analysis of data recorded in experiment. It has been shown that properties of dynamics of nucleation sites changes nonlinearly together with changing the spacing between cavities. To explain appearance of such properties of nucleation sites interaction the simulation of gas bubble movement in the liquid in the last stage of bubble departures has been made with using the stabilized finite element method and level set method. It has been shown that the bubble departure velocities and structure of velocity field around the bubbles nonlinearly depend on the initial horizontal spacing between bubbles. The obtained results indicate that one of the reasons for nonlinear changes of properties of dynamics of nucleation sites interaction occurring with changes of initial spacing between them is hydrodynamic interaction between departing bubbles. (c) 2007 Elsevier Ltd. All rights reserved.