title: Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry.
abstract: A drop impacting on a solid surface deforms before the liquid makes contact with the surface. We directly measure the time evolution of the air layer profile under the droplet using high-speed color interferometry, obtaining the air layer thickness before and during the wetting process. Based on the time evolution of the extracted profiles obtained at multiple times, we measure the velocity of air exiting from the gap between the liquid and the solid, and account for the wetting mechanism and bubble entrapment. The present work offers a tool to accurately measure the air layer profile and quantitatively study the impact dynamics at a short time scale before impact.
authors.affiliation: Physics of Fluids, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Roeland C A
authors.initials: RC
authors.lastname: van der Veen
authors.forename: Tuan
authors.initials: T
authors.lastname: Tran
authors.forename: Detlef
authors.initials: D
authors.lastname: Lohse
authors.forename: Chao
authors.initials: C
authors.lastname: Sun