Analysis of breaking and re-closure of a bubble near a free surface based on the Eulerian finite element method

The nonlinear interaction between a bubble and a nearby free surface is an important phenomenon, which becomes more complex when the bubble breaks and re-closes at the free surface. In this paper, an axisymmetric bubble dynamics model based on the Eulerian finite element method with the interface tracked by the volume of fluid (VOF) method is established to numerically investigated the breaking and re-closure of a bubble near a free surface. An experimental validation of the numerical model reveals its good accuracy. The motion, breaking, and re-closure of small and large bubbles at a free surface are simulated. Complex phenomena are observed in the simulation after the break of the bubble. Under the effects of inward gas flow and the pressure difference between its inside and outside, a broken bubble finally recloses. The convergence and impact of a spike wall generate an upward water spray higher than that from an intact bubble. Furthermore, the critical depth at which the bubble period reaches its peak has a negative relationship with the weight of the explosive charge used to generate the bubble.