title: Impact of a viscous liquid drop.
abstract: We simulate the impact of a viscous liquid drop onto a smooth dry solid surface. As in experiments, when ambient air effects are negligible, impact flattens the falling drop without producing a splash. The no-slip boundary condition at the wall produces a boundary layer inside the liquid. Later, the flattening surface of the drop traces out the boundary layer. As a result, the eventual shape of the drop is a "pancake" of uniform thickness except at the rim, where surface tension effects are significant. The thickness of the pancake is simply the height where the drop surface first collides with the boundary layer.
authors.affiliation: Physics Department and the James Franck Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Schroll
authors.forename: Christophe
authors.initials: C
authors.lastname: Josserand
authors.forename: Stéphane
authors.initials: S
authors.lastname: Zaleski
authors.forename: Wendy W
authors.initials: WW
authors.lastname: Zhang