Dynamics of a bubble in a liquid fully confined by an elastic boundary

In order to investigate the dynamics of a bubble in a liquid fully confined by an elastic boundary, which are used for applications and research of cavitation bubbles in botanical and biomedical sciences, we establish a related numerical model by the boundary element method. The boundary is defined as an interface between two liquids with different densities to simulate the environment of biological tissue efficiently. Our numerical model is validated thanks to the results of an available related experiment and the calculations of a confined corrective Rayleigh–Plesset equation. Then, we focus on the dynamics of a non-spherical bubble caused by relative position of the bubble and confinement. The results show that the confinement can lead to a rapid oscillation of a bubble, and a jet will be generated along the eccentric direction because of the accumulation of high pressure and disturbance on one side of the spherical confinement. Furthermore, elastic modulus of the boundary, size of the confinement, and eccentric position of the bubble in the confinement are considered in this paper. The amplitude and cycle of a bubble oscillation will decrease with the increase of the elastic modulus and decrease of the size of the confinement. What's more, eccentricity leads to a strong restriction on the bubble surface near the boundary and obvious non-spherical deformation of the elastic boundary. The study can contribute to understandings and applications of cavitation bubbles in expulsion of spores, plant cell wall broken, thrombolysis, and other related botanical and biomedical fields.