Bubble dynamics in non-Newtonian fluids

Cavitation Rheology (CR) has been investigated as a novel technique for the characterization of the elastic and fracture properties of soft materials. In addition to measuring mechanical properties of solids, the formation and pressurization of a cavity, as dictated by some initial defect size, is an information-rich phenomenon that can illuminate the interfacial properties of fluids undergoing hydrostatic deformation. In this presentation, we explore the use of CR as a probe for the fluid properties of materials that display both Newtonian and non-Newtonian behavior. By tracking the evolution of the pressure inside the bubble and carefully analyzing the geometry of the bubble wall, we gain insight into properties of the fluid such as viscosity, bulk modulus and Poisson’s ratio. For the case of a model shear thickening fluid, we observe pressurization rate dependence on the critical cavitation pressure and evidence of transient fracture at sufficiently high pressurization rates. Our observations have deep implications in advancing the study of high-rate deformation of non-Newtonian fluids and soft materials.