Impact dynamics of egg-shaped drops on a solid surface for suppression of the bounce magnitude

Abstract

Enhancement of drop deposition is advantageous in various fields, such as painting, cooling, and agricultural spraying. We present a method to suppress the bounce magnitude of a drop on nonwetting solid surfaces via asymmetrical shaping. Numerical results show that the asymmetrical drop shape can substantially alter the hydrodynamics, thereby leading to a reduction in bounce height by nearly 55% on hydrophobic surfaces compared with the spherical shape. To elucidate how the shape affects the bounce magnitude, we scrutinize the asymmetrical hydrodynamic features in spreading and retraction and the quantitative analysis of momentum for varying geometric parameters, revealing that enhancement of asymmetry in the horizontal momentum plays a vital role in suppressing bounce magnitude. The asymmetrical drop impact can provide implications for exploiting dynamic scenarios of drops, such as fusion of sprayed drops in unequal size and drop manipulation in microfluidics.