The effect of viscoelasticity on the dynamics of two gas bubbles near a rigid boundary

Abstract

Multi-bubble dynamics is investigated in the presence of a rigid boundary. A simplified configuration is considered in which two bubbles, not necessarily of the same size, are positioned along an axis of symmetry. The problem is formulated in terms of a generalized Bernoulli equation for a velocity potential. A boundary element method is adopted to determine the normal velocity at the bubble surface. Viscoelastic effects are incorporated into the model through the normal stress balance across the bubble surface. The model predicts that bubble dynamics, and jet formation, in particular, is strongly influenced by the initial bubble sizes, the initial stand-off distances and on the fluid parameters. Viscoelastic effects are shown to be responsible for some interesting dynamics. Although inter-bubble interaction is shown to play an important role, it is not always dominant for viscoelastic fluids.