Singular jets in free-surface flows
Presenter
July 17, 2008
Keywords:
- Jets
MSC:
- 58A20
Abstract
Free-surface 'singular jetting' occurs in geometries where flow
focusing accelerates the free surface symmetrically towards a
line or a point. This is known to occur in a number of
configurations, such as during the collapse of free-surface
craters and of granular cavities as well as for capillary waves
converging at the apex of oscillating drops. Drops impacting
onto super-hydrophobic surfaces also generate such jets. We
will show recent work on characterizing such jetting, in
well-known and new jetting configurations. High-speed video
imaging, with frame-rates up to 1,000,000 fps, will be
presented and used for precise measurement of jet size and
velocity. The focus will be on three well-controlled
flow-configurations: During the crater collapse following the
impact of a drop onto a liquid pool and after the pinch-off of
a drop from a vertical nozzle. Finally, we will show a new
apex jet which is generated by the impact of a viscous drop
onto a lower-viscosity pool.