  The majority of studies on self-propelled particles and microswimmers
concentrates on objects that do not feature a deterministic bending of their
trajectory. However, perfect axial symmetry is hardly found in reality, and
shape-asymmetric active microswimmers tend to show a persistent curvature of
their trajectories. Consequently, we here present a particle-scale statistical
approach of circle-swimmer suspensions in terms of a dynamical density
functional theory. It is based on a minimal microswimmer model and,
particularly, includes hydrodynamic interactions between the swimmers. After
deriving the theory, we numerically investigate a planar example situation of
confining the swimmers in a circularly symmetric potential trap. There, we find
that increasing curvature of the swimming trajectories can reverse the
qualitative effect of active drive. More precisely, with increasing curvature,
the swimmers less effectively push outwards against the confinement, but
instead form high-density patches in the center of the trap. We conclude that
the circular motion of the individual swimmers has a localizing effect, also in
the presence of hydrodynamic interactions. Parts of our results could be
confirmed experimentally, for instance, using suspensions of L-shaped circle
swimmers of different aspect ratio.
