Application of two-phase transition model in underwater explosion cavitation based on compressible multiphase flows

Underwater explosion cavitation is generally simulated using a one-fluid model based on compressible multicomponent flows. Owing to the lack of mass and heat transfer between liquid and vapor phases, this model is incapable of extensively analyzing the cavitation mechanism in underwater explosion. In this study, we extend the phase transition model provided by Chiapolino et al. to the field of underwater explosion cavitation. The model presents a more accurate description of the thermodynamics of cavitation processes involving liquid–vapor phase transition. The numerical results show that the phase transition exhibits significant potential in the study of underwater explosion cavitation, and the likely occurrence of creation, development, and collapse of the cavitation can be captured. A vortex band composed of a large number of tiny cavitation bubbles can be observed in the numerical results, which is consistent with the experiment in underwater explosion near a free surface. The variation range of the cavitation domain calculated by the phase transition model is basically consistent with the experiment, which proves the reliability and accuracy of the calculation model. Meanwhile, the distribution characteristics of quantities such as density, pressure, and vapor phase volume fraction in the cavitation domain can be effectively obtained in simulation, which are usually difficult to capture in experiments. The creation mechanism of cavitation near a free surface and rigid wall is different. However, the collapse mechanism is similar. The results of this study could provide an in-depth understanding of the dynamic behavior of cavitation in underwater explosion.