Abstract
Active fluids generate spontaneous, often chaotic mesoscale flows. Harnessing
these flows to drive embedded soft materials into structures with controlled
length scales and lifetimes is a key challenge at the interface between the
fields of active matter and nonequilibrium self-assembly. Here, we present a
simple and highly efficient computational approach to model soft materials
advected by active fluids, by simulating particles moving in a spatiotemporally
correlated noise field. The algorithm enables orders of magnitude speed up in
comparison to other methods. To illustrate our approach, we simulate the
dynamical self-organization of repulsive colloids within such an active noise
field in two and three dimensions. The colloids form structures whose sizes and
dynamics can be tuned by the correlation time and length of the active fluid,
and range from small rotating droplets to clusters with internal flows and
system-spanning sizes that vastly exceed the active correlation length. Our
results elucidate how the interplay between active fluid time/length scales and
emergent driven assembly can be used to rationally design functional
assemblies. More broadly, our approach can be used to efficiently simulate
diverse active fluids and other systems with spatiotemporally correlated noise.