Numerical simulations of inertial microcavitation near a gel-water interface with finite elasticity and phase change*

Inertial cavitation induces finite, high-strain rate deformations in soft materials during high impact events, such as boxing, football, blasts, and traumatic brain injury. Inertial cavitation and material viscoelasticity have been explored for spherical bubble dynamics in homogeneous environments; the interactions of impacts in a multi-material environment with nonlinear bubble dynamics are poorly understood. The bubble dynamics and surrounding material elasticity are coupled in a non-linear fluid-structure interaction. We conduct 3D simulations of bubble growth and collapse near a tissue-like gel-water material interface. We use the open-source Multi-component Flow Code [Radhakrishnan & Le Berre et al. Comp. Phys. Comm. (2024)] which solves the compressible flow equations using a 6-equation multiphase model with a phase change model and accounts for hyperelasticity in solids using reference mapping [Kamrin et al. J. Mech. Phys. Sol. (2012)] for compressible neo-Hookean materials. We present qualitative comparisons between numerical simulations and gel-water experiments of strains, displacements, streamlines, and kymographs. The pressure and stress contours are compared for each stand-off distances throughout the bubble's evolution to discern the bubble dynamics and material deformation.