Tests of Dynamical Scaling in 3-D Spinodal Decomposition

TL;DR

This study uses simulations to examine late-stage coarsening in 3-D binary fluids, revealing persistent viscous hydrodynamic scaling but with variations suggesting additional lengthscales or slow regime crossovers.

Contribution

It extends previous simulations by two decades in time and critically analyzes the validity of viscous scaling in 3-D spinodal decomposition.

Findings

Viscous hydrodynamic scaling observed over four decades.

Scaling coefficient b varies between runs, indicating non-uniformity.

Potential influence of discretization or molecular lengthscales.

Abstract

We simulate late-stage coarsening of a 3-D symmetric binary fluid. With reduced units l,t (with scales set by viscosity, density and surface tension) our data extends two decades in t beyond earlier work. Across at least four decades, our own and others' individual datasets (< 1 decade each) show viscous hydrodynamic scaling (l ~ a + b t), but b is not constant between runs as this scaling demands. This betrays either the unexpected intrusion of a discretization (or molecular) lengthscale, or an exceptionally slow crossover between viscous and inertial regimes.