title: von Kármán vortex street within an impacting drop.
abstract: The splashing of a drop impacting onto a liquid pool produces a range of different sized microdroplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultrahigh-speed video imaging in combination with high-resolution numerical simulations to show how this ejecta gives way to irregular splashing. At higher Reynolds numbers, its base becomes unstable, shedding vortex rings into the liquid from the free surface in an axisymmetric von Kármán vortex street, thus breaking the ejecta sheet as it forms.
authors.affiliation: Division of Physical Sciences and Engineering & Clean Combustion Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Marie-Jean
authors.initials: MJ
authors.lastname: Thoraval
authors.forename: Kohsei
authors.initials: K
authors.lastname: Takehara
authors.forename: Takeharu Goji
authors.initials: TG
authors.lastname: Etoh
authors.forename: Stéphane
authors.initials: S
authors.lastname: Popinet
authors.forename: Pascal
authors.initials: P
authors.lastname: Ray
authors.forename: Christophe
authors.initials: C
authors.lastname: Josserand
authors.forename: Stéphane
authors.initials: S
authors.lastname: Zaleski
authors.forename: Sigurdur T
authors.initials: ST
authors.lastname: Thoroddsen