Jeffrey M. Aristoff

Water entry of small hydrophobic spheres

We present the results of a combined experimental and theoretical investigation of the normal impact of hydrophobic spheres on a water surface. Particular attention is given to characterizing the shape of the resulting air cavity in the low Bond number limit, where cavity collapse is driven principally by surface tension rather than gravity. A parameter study reveals the dependence of the cavity structure on the governing dimensionless groups. A theoretical description based on the solution to the Rayleigh–Besant problem is developed to describe the evolution of the cavity shape and yields an analytical solution for the pinch-off time in the zero Bond number limit. The spheres depth at cavity pinch-off is also computed in the low Weber number, quasi-static limit. Theoretical predictions compare favourably with our experimental observations in the low Bond number regime, and also yield new insight into the high Bond number regime considered by previous investigators. Discrepancies are rationalized in terms of the assumed form of the velocity field and neglect of the longitudinal component of curvature, which together preclude an accurate description of the cavity for depths less than the capillary length. Finally, we present a theoretical model for the evolution of the splash curtain formed at high Weber number and couple it with the underlying cavity dynamics.

The influence of surface tension on the circular hydraulic jump

We present the results of a combined theoretical and experimental investigation of the influence of surface tension

How Cats Lap: Water Uptake by Felis catus

\sigma

An experimental investigation of the stability of the circular hydraulic jump

on the laminar circular hydraulic jump. An expression is deduced for the magnitude of the radial curvature force per unit length along a circular jump,

Gravity-induced encapsulation of liquids by destabilization of granular rafts

F_c\,{=}\,{-}\sigma ( s - \uDelta R )/R_j

Dynamics of elastocapillary rise

, where

Viscous Hydraulic Jumps

R_j

The water-entry cavity formed by low Bond number impacts

is the jump radius, and

Water bell and sheet instabilities

s

Imbibition of concentrated suspensions in capillaries

and