Coalescence of pendent drops
Abstract
We use a novel ultra-high-speed video camera to observe the capillary-driven coalescence motions when a pendent and a sessile drop touch at their tips. The earliest motions are observed using a 5 micro-second temporal resolution and a long-distance microscope. Triggering is based on electrical contact between the two drops. Motion occurs slightly after electrical contact is established. We construct a capillary-inertial model based on the spacing of the two free surfaces. This model successfully predicts the coalescence speed for low-viscosity drops, over a range of drop sizes. The effects of drop viscosity are also investigated, using glycerin/water mixtures. The neck-shapes are observed to become progressively sharper as the viscosity increases.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2003
- Bibcode:
- 2003APS..DFD.AF006T