NEW HYDRODYNAMIC MECHANISM FOR DROP COARSENING

We discuss a new mechanism of drop coarsening due to coalescence only, which describes the late stages of phase separation in fluids. Depend ing on the volume fraction of the minority phase, we identify two diff erent regimes of growth, where the drops are interconnected and their characteristic size grows linearly with time, and where the spherical drops are disconnected and the growth follows (time)(1/3). The transit ion between the two regimes is sharp and occurs at a well defined volu me fraction of order 30%.