STUDY ON THE INFLUENCE OF MIGRATION CHARACTER PARAMETERS FOR UNDERWATER EXPLOSION BUBBLES BASED ON THE UNIFIED EQUATION FOR BUBBLE DYNAMICS

The unified bubble equation can describe the behavior of spherical bubble dynamics considering multiple factors efficiently, but it is still ambiguous to describe the influence of the characteristic parameters in the bubble migration equation on the behavior of bubbles as well as how to determine the characteristic parameters. In this paper, a theoretical model is established based on the unified equation of bubbles for computation, compared with the numerical algorithm of the "Euler finite element method" and the classic theoretical models of spherical bubbles, and together with the underwater explosion experiments to further verify the scientific validity of the unified equation of bubbles and the advantages over other theoretical models. On this basis, the influence of the characteristic parameters of the migration equation on the dynamics of free-field underwater explosion bubbles is investigated. It is shown that the drag force coefficient and the additional mass coefficient have negligible effects on bubble oscillation during the first period, while the drag force coefficient is more dominant than the additional mass coefficient on bubble migration. When the drag force coefficient is large, it has a significant barrier effect on bubble migration; on the contrary, it is not sufficient to provide a barrier effect. The additional mass coefficient is also a barrier to bubble migration, with a nearly linear effect. The determination of migration characteristic parameters needs to be analyzed around the specific problem, and based on the results of the study and combined with similar experiments, the migration characteristic parameters can be clarified, and then the theoretical computation can provide guidance and reference for the practical engineering applications of underwater explosions.