Inertial interface cavitation creates complex, flow-like structures within a soft solid

Inertial interface cavitation is a well-appreciated phenomenon in many natural, biological, and physical processes. The existence of impedance changes across an interface can generate complex fluid motion within a fluid but whether such motion persists, or is similar, within the adjacent solid has yet to be determined. Here, by leveraging recent technological advances in quantitative full-field imaging, deformation/motion characterization, and laser-based cavitation, we document the complex deformation fields that arise in a model soft solid of gelatin during interfacial cavitation. Specifically, we identify stagnation points, vortex pairs, and vortex ring-like structures as a function of the cavitation bubble standoff distance within the solid, for which we identify four distinct regimes. While two of the regimes have been previously studied, we show that the additional two regimes close to the interface generate most of the complex, fluid-like deformations within the gel. Finally, we quantify the associated material stresses and residual, permanent strains that can occur during such events providing both length and time scale estimates of the destructive power of cavitation.