Dimple and nose coalescences in phase-separation processes.

Abstract

Coalescence processes are investigated during phase separation in a density-matched liquid mixture (partially deuterated cyclohexane and methanol) under near-critical conditions. As a result of the interplay between capillary and lubrication forces, ``nose'' coalescence appears to be always associated with the slow growth of isolated droplets (exponent \ensuremath{\approxeq}1/3), whereas ``dimple'' coalescence corresponds to the fast growth of interconnected droplets (exponent \ensuremath{\approxeq}1). At each stage of growth, the distribution of droplets trapped during dimple coalescence is reminiscent of all of the previous coalescence events.