Simulation of bubble expansion and collapse in the vicinity of a freesurface

The present paper focuses on the numerical simulation of the interaction oflaser-generated bubbles with a free surface, including comparison of the resultswith instances from high-speed videos of the experiment. The Volume Of Fluid methodwas employed for tracking liquid and gas phases while compressibility effects wereintroduced with appropriate equations of state for each phase. Initial conditions of thebubblepressure wereestimated through the traditional Rayleigh Plesset equation. The simulatedbubbleexpands in a non-spherically symmetric way due to the interference of thefreesurface, obtaining an oval shape at the maximum size. Duringcollapse, a jet with mushroom cap is formed at the axis of symmetry with thesame direction as the gravity vector, which splits the initial bubble to anagglomeration of toroidal structures. Overall, the simulation results are inagreement with the experimental images, both quantitatively and qualitatively, whilepressurewaves are predicted both during the expansion and the collapse of the bubble. Minordiscrepancies in the jet velocity and collapse rate are found and are attributed tothe thermodynamic closure of the gas inside the bubble.