Interplay between viscosity and elasticity in freely expanding liquid sheets

We investigate the dynamics of freely expanding liquid sheets prepared with fluids with different rheological properties, (i) viscous fluids with a zero-shear viscosity $\eta_0$ in the range $(1-1000) \, \mathrm{mPa.s}$ and (ii) viscoelastic Maxwell fluids whose elastic modulus, $G_0$, characteristic relaxation time, $\tau$, and zero-shear viscosity, $\eta_0=G_0 \tau$, can be tuned over several orders of magnitude. The sheets are produced by impacting a drop of fluid on a small cylindrical solid target. For viscoelastic fluids, we show that, when $\tau$ is shorter than the typical lifetime of the sheet ($\sim 10$ ms), the dynamics of the sheet is similar to that of Newtonian viscous liquids with equal zero-shear viscosity. In that case, for little viscous samples ($\eta_0
Comment: 10 pages, 9 figures