Airflow-Assisted Impact of Drops of Various Viscosities: The Role of Viscous Dissipation, Normal Imposed Pressure, and Shear Flow of Air.

The role of liquid viscosity on the spreading for an airflow-assisted impact of drops on a surface is investigated. The spreading diameter is found to increase with the Reynolds number of the airflow () for a given viscosity and impact Weber number () compared to the still air. The increment is higher at a low for viscous drops, whereas the effect of dominates at the intermediate as the viscosity decreases.