FIG. 5.

Shape recovery curves at a finite viscosity ratio between the droplet and bulk phases. (a) Comparison of $f_2\left(t\right)$ for three cases of pairing interior and exterior fluids: Newtonian with Newtonian (solid curves), viscoelastic with Newtonian (dotted curves), and Newtonian with viscoelastic (dashed curves). The viscosity ratios, i.e., η_II/η_I, are shown in the legend. Viscoelasticity is given by the Jeffreys model, with η₀/η₁ = 1:5 and ${\tau }_1^{\mathrm{s}\mathrm{r}}\gamma /{\eta }_{\mathrm{I}}R$ = 10. (b) Comparison of our analytical results (curves) with experimental data of Verhulst et al. (symbols) for five systems, all with η_II/η_I = 1.5. The viscoelasticity was reported as fitting to the Oldroyd B model, with η₀/η₁ ≈ 2:1 and ${\tau }_1^{\mathrm{s}\mathrm{r}}\gamma /{\eta }_{\mathrm{I}}R$ indicated in the legend. Curves and symbols have matching colors for the same systems.