  The late-stage demixing following spinodal decomposition of a
three-dimensional symmetric binary fluid mixture is studied numerically, using
a thermodynamicaly consistent lattice Boltzmann method. We combine results from
simulations with different numerical parameters to obtain an unprecendented
range of length and time scales when expressed in reduced physical units. Using
eight large (256^3) runs, the resulting composite graph of reduced domain size
l against reduced time t covers 1 < l < 10^5, 10 < t < 10^8. Our data is
consistent with the dynamical scaling hypothesis, that l(t) is a universal
scaling curve. We give the first detailed statistical analysis of fluid motion,
rather than just domain evolution, in simulations of this kind, and introduce
scaling plots for several quantities derived from the fluid velocity and
velocity gradient fields.
