Three-dimensional direct numerical simulation of shock-induced bubble collapse near gelatin

We present fully three-dimensional numerical simulation results of shock-induced bubble collapse near a water-gelatin interface. We study how the incoming pulse form and its amplitude affect the dynamics of bubble collapse and the subsequent gelatin penetration. Three immiscible fluids (water, air, and gelatin) are considered, separated by a sharp interface (level set). A conservative interface-interaction model determines the exchange of momentum and energy. A block-structured multiresolution scheme is used to adapt the mesh to the evolving flow field. Validation simulations (free-field bubble collapse, bubble collapse near a rigid wall) show that our numerical setup accurately predicts bubble collapse dynamics and post-collapse wave dynamics. Two-dimensional simulations assuming cylindrical symmetry reveal a quasi self-similar collapse behavior of the bubble for each wave form. The gelatin-penetration dynamics are self-similar, too, and occur in three stages. The onset of the gelatin penetration is governed by the post-shock momentum after the bubble collapse. This is followed by a fast penetration upon the impact of the water hammer. The penetration rate slows down once interfacial instabilities grow at the water-gelatin interface. Our three dimensional simulation results confirm the two-dimensional cylindrically-symmetric results of a single-bubble collapse. The collapse of two equi-sized bubbles results in a change of direction of the emitted water hammers. For our setup, the water hammers are deflected in the direction of the second bubble, and therefore impinge on the gelatin interface obliquely. The actual direction depends on the initial bubble separation distance and the stand-off distance from the interface, and will be further investigated in future work. © 2019 International Symposium on Turbulence and Shear Flow Phenomena, TSFP. All rights reserved.     «

We present fully three-dimensional numerical simulation results of shock-induced bubble collapse near a water-gelatin interface. We study how the incoming pulse form and its amplitude affect the dynamics of bubble collapse and the subsequent gelatin penetration. Three immiscible fluids (water, air, and gelatin) are considered, separated by a sharp interface (level set). A conservative interface-interaction model determines the exchange of momentum and energy. A block-structured multiresolution s...     »