title: Buckling of liquid columns.
abstract: Under appropriate conditions, a column of viscous liquid falling onto a rigid surface undergoes a buckling instability. Here we show experimentally and theoretically that liquid buckling exhibits a hitherto unsuspected complexity involving three different modes-viscous, gravitational, and inertial-depending on how the viscous forces that resist bending of the column are balanced. We also find that the nonlinear evolution of the buckling exhibits a surprising multistability with three distinct states: steady stagnation flow, "liquid rope coiling," and a new state in which the column simultaneously folds periodically and rotates about a vertical axis. The transitions among these states are subcritical, leading to a complex phase diagram in which different combinations of states coexist in different regions of the parameter space.
authors.affiliation: Institute for Advanced Studies in Basic Sciences, Zanjan 45195-1159, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Habibi
authors.forename: Y
authors.initials: Y
authors.lastname: Rahmani
authors.forename: Daniel
authors.initials: D
authors.lastname: Bonn
authors.forename: N M
authors.initials: NM
authors.lastname: Ribe