Numerical simulation of interaction between bubble and free surface considering flow field viscosity

Abstract

ObjectiveThis study investigates the evolution of the interaction between an underwater explosion bubble and the free liquid surface in terms of compressibility and viscous effect. MethodsA numerical model of an underwater explosion bubble coupled with the free liquid surface is developed on the basis of the compressible two-phase flow solver of OpenFOAM and the volume of fluid method (VOF). The validity of the numerical model is then verified by comparison with the experimental results. The effects of different flow field viscosities and distance parameters on the bubble pulsation process and free-surface spike motion are also investigated. ResultsThe flow field viscosity effect has an important influence on the surface spike height, bubble pulsation period and bubble pulsation, especially the bubble morphology in the rebound phase. Ring bubble morphology is not easy to maintain in low viscosity fluid, so the tearing phenomenon of the bubble can easily occur. As the distance parameter increases, the coupling effect between the free surface and the bubble gradually decreases, the bubble pulsation period increases, the heights of the primary and secondary surface spikes decrease, and the widths of the primary spike and liquid jet gradually increase.ConclusionThe results of this study can provide useful references for determining the evolution mechanism of bubbles under different flow field viscosities.

Keywords

• underwater explosion bubble
• free surface
• flow field viscosity
• distance parameter
• free-surface spike