Rebound Of Large Jets From Superhydrophobic Surfaces In Low Gravity

We experimentally investigate the phenomena of large liquid jet rebound, a mode of fluid transfer following oblique jet impacts on superhydrophobic substrates. We initially seek to describe the jet rebound regimes in tests conducted in the weightless environment of a drop tower. A parametric study reveals the dependence of the flow structure on the relevant dimensionless groups such as Reynolds number and Weber number defined on the velocity component perpendicular to the substrate. We show that significantly larger diameter jets behave similarly as much smaller jets demonstrated during previous terrestrial investigations in some parameter ranges while the flow is fundamentally different in others. Level-set numerical predictions are provided for comparisons where practicable. Simple models are developed predicting landing geometry and the onset of instability that are found to yield good agreement with experiments and simulations. Improving our understanding of such jet rebound opens avenues for unique transport capabilities.