49 research outputs found
Droplet detachment and bead formation in visco-elastic fluids
Get PDFThe presence of a very small amount of high molecular weight polymer
significantly delays the pinch-off singularity of a drop of water falling from
a faucet, and leads to the formation of a long-lived cylindrical filament. In
this paper we present experiments, numerical simulations, and theory which
examines the pinch-off process in the presence of polymers. The numerical
simulations are found to be in excellent agreement with experiment. As a test
case, we establish the conditions under which a small bead remains on the
filament; we find that this is due to the asymmetry induced by the self-similar
pinch-off of the droplet.Comment: 4 pages, 4 figure
Giant diffusion of nanomechanical rotors in a tilted washboard potential
Full text linkWe present an experimental realization of a biased optical periodic potential
in the low friction limit. The noise-induced bistability between locked
(torsional) and running (spinning) states in the rotational motion of a
nanodumbbell is driven by an elliptically polarized light beam tilting the
angular potential. By varying the gas pressure around the point of maximum
intermittency, the rotational effective diffusion coefficient increases by more
than 3 orders of magnitude over free-space diffusion. These experimental
results are in agreement with a simple two-state model that is derived from the
Langevin equation through using timescale separation. Our work provides a new
experimental platform to study the weak thermal noise limit for diffusion in
this system
