（a）Rotator crystals in a monolayer of vertically vibrated discs;(b)Growing drops on an inclined plane: evolution of shape
Experimentalphysik V, Universität Bayreuth, 95440 Bayreuth, Germany
(a)Rotator crystals in a monolayer of vertically vibrated discs
Abstract: The collective behaviour of vertically vibrated hexagonal disks confined in a horizontal monolayer is investigated experimentally. The disks tend to rotate upon sufficiently strong driving. Additionally, they can arrange in a hexagonal structure, reminiscent of a rotator crystal in equilibrium systems. We investigate the transitions into and out of this non-equilibrium steady state. Furthermore we characterize the rotator crystal state using the bond orientational order parameter and parameters coupled with set voronoi diagrams. Finally we explore the influence of the confinement by varying the container height systematically.
(b)Growing drops on an inclined plane: evolution of shape
Abstract: Liquid drops sitting on or running down an inclined plane are ubiquitous in our daily lives. Their sliding can be triggered by tilting the surface at a fixed drop volume or by increasing the drop volume at a fixed inclination angle. Here, we present experiments on the latter protocol. Therefore we employ a conventional inkjet printhead,which provides a volume resolution of 23 picoliters, high repeatability, as well as the flexibility of following the drop's development by selecting different nozzles. Based on an analysis of both top view and side view images, we explore the evolution of the drop shape in the vicinity of the depinning transition and compare our results with numerical simulations.