Influence of a local change of depth on the behavior of walking oil drops

• Published in: Experimental thermal and fluid science Vol. 54; pp. 237 - 246
• Main Authors: Carmigniani, R., Lapointe, S., Symon, S., McKeon, B.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.04.2014; Elsevier
• Subjects: Acceleration; Bouncing; Bouncing drops; Change of depth; Droplets; Drops and bubbles; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Hydrodynamic waves; Liquids; Nonhomogeneous flows; Obstacles; Particle-wave interaction; Physics; Pilot wave theory; Submerging; Trapping; Walking; Walking drops; Bouncing drops; Particle-wave interaction; Pilot wave theory; Change of depth; Walking drops; Test facilities; Obstacle; Immersed body; Silicone oil; Liquid layer; Experimental study; Surface waves; Wave propagation; Drops; Rebound; Interactions
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2013.12.023

•The influence of change of depth on walking of oil drops explored.•Previously unreported drop trajectories observed.•Results explained in light of recent results and models in the literature. Bouncing liquid silicone oil drops on a vertically oscillating bath of the same liquid were studied experimentally. The different bouncing regimes previously described in the literature were observed, with transitions depending mainly on the droplet size and the forcing acceleration of the oil bath. In a particular range of forcing amplitudes, just below the Faraday instability threshold where standing waves appear on the free surface, walking drops traveling at a constant velocity over the surface were observed, consistent with previous studies. The influence of a local change of depth on this walking behavior was studied by submerging an obstacle in the oil bath. Notably different to the study of Eddi et al. (2009) [1], the depth change was such that walking was still observed over the obstacle. Previously unobserved drop trajectories, including trapping of a walking drop over the obstacle, crossing for non-normal drop approach to the obstacle, and reflection from the rear face of the obstacle were observed and explained in light of recent results and models in the literature.