Phase ordering of two-dimensional symmetric binary fluids: A droplet scaling state

The late-stage phase ordering, in d=2 dimensions, of symmetric fluid mixtures violates dynamical scaling. We show however that, even at 50/50 volume fractions, if an asymmetric droplet morphology is initially present then this sustains itself, throughout the viscous hydrodynamic regime, by a coalescence-induced coalescence mechanism. Scaling is recovered ( with length scale l similar tot, as in d=3). The crossover to the inertial hydrodynamic regime is delayed even longer than in d=3; on entering it, full symmetry is finally restored and we nd l similar tot(2/3), regardless of the initial state.