Driven bubble dynamics with coupled vaporization and non-Newtonian relaxation time scales

In cavitation-based therapeutic applications, the rheological and thermodynamic properties of the surrounding generalized Newtonian fluid play a crucial role. The effects of these properties are, however, often studied in isolation. We study the influence of the interaction of non-Newtonian viscous behavior with phase transition on spherically symmetric cavitation dynamics. The overlap of time scales associated with these phenomena leads to interesting effects on bubble dynamics. In particular, during collapse in a Carreau shear thinning fluid, we report lower first minimum radii (R_min) for a range of values of relaxation time constant (λ) compared with that obtained using the minimum viscosity value (λ approaches infinity) of the Carreau model. R_min versus λ profile attains a minimum value in this range, where we obtain significant (up to orders of magnitude depending upon shear thinning and phase transition parameters) reduction in R_min.