  We study dynamics of clustering in systems containing active particles that
are immersed in an explicit solvent. For this purpose we have adopted a hybrid
simulation method, consisting of molecular dynamics and multi-particle
collision dynamics. In our model, overlap-avoiding passive interaction of an
active particle with another active particle or a solvent particle has been
taken care of via variants of Lennard-Jones potential. Dynamic interaction
among the active particles has been incorporated via the Vicsek-like
self-propulsion that facilitates clustering. We quantify the effects of
activity and importance of hydrodynamics on the dynamics of clustering via
variations of relevant system parameters. We work with low overall density of
active particles. For this the morphology consists of disconnected clusters,
the mechanism of growth switching among particle diffusion, diffusive
coalescence and ballistic aggregation, depending upon the presence or absence
of active and hydrodynamic interactions. Corresponding growth laws have been
quantified and discussed in the background of appropriate theoretical pictures.
Our results suggest that multi-particle collision dynamics is an effective
method for investigation of hydrodynamic phenomena even in active matter
systems.
