Figure 14.

Evolution of a scalar field s(x,y,z,t), which is initially given by a one-dimensional sinusoidal distribution s(x,y,z,0) = sin(2πx/L) and is passively advected by the velocity fields of figure 2. The figure only shows a planar slice at constant z. The different rows correspond to Pushers at effective volume fractions (a) ν = 0.1, (b) ν = 0.5, (c) ν = 1.0 and (d) Pullers with ν = 1.0. Also see the accompanying online movie (electronic supplementary material). (Online version in colour.)