ИСТИНА

The gas bubble subjected to an acoustic wave in liquid is considered. The wave frequency is considered to be equal to the resonant frequency for the bubble radial oscillations and its magnitude is considered to be not very high in order the cavitation not to appear. The problem of a gas bubble break-up in liquid is considered in the conditions of the frequencies resonance of the radial and nth axially symmetric deformational mode 2:1. The nonlinear energy transfer between the modes is described using an efficient Krylov-Bogolyubov averaging technique. The approach proposed describes well qualitatively the process at its start and quantitatively at its finish. It is shown that the deformational mode magnitude can be some orders larger than the radial mode magnitude. The thermal, viscous and acoustic dissipation mechanisms for the oscillating bubble are considered in the linear approximation. The estimative criterion of the bubble break-up is obtained in the cases of smooth and sudden acoustic wave start. The obtained pressure magnitudes in the wave for break-up are of the order of kilopascals and the mechanism can have strong medical and technical applications. For example the mechanism may be used to open the blood-brain barrier in the brain drug delivery problems.