An experimental investigation on impact process of Boger drops onto solid surfaces

In this paper, the impact dynamics of Boger drops on dry solid surfaces is investigated experimentally. The effects of viscosity, surface wettability, and impact velocity on the spreading and receding behavior of the Newtonian and viscoelastic drops are studied in detail. They are impinged upon Plexiglas and glass substrates, which have hydrophilic properties, at the impact velocities 4.03 m/s and 4.22 m/s. The polyacrylamide drops spread out more widely and recede more rapidly than the glycerin drops. The impact velocity and the liquid viscosity have more influence on the spreading phase. However, the surface wettability shows only a minute effect on the spreading phase but a very significant effect on the receding phase. On the receding stage, the effect of impact velocity was only observed on the behavior of the low-viscosity drops. Therefore, when the low-viscosity drops impact on a hydrophilic substrate, the higher impact velocity, the receding velocity is increased.