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. Depending on the volume fraction of the minority phase, we identify two different 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 transition between the two regimes is sharp and occurs at a well defined volume fraction of order 30%.