  We study the shear-induced behavior of chiral (circle-swimming) and nonchiral
swimmers in a planar channel subjected to Poiseuille (pressure-driven) flow.
The swimmers are modeled as active Brownian spheroids, self-propelling with a
fixed-magnitude velocity, pointing along their axis of symmetry. We consider
both cases of prolate and oblate swimmers and focus primarily on swimmers that
possess an intrinsic, or active, counterclockwise angular velocity, in addition
to the shear-induced angular velocity they acquire within the channel flow
(Jeffery orbits). The probabilistic results are established using a
Smoluchowski equation within the position orientation phase space that is
solved numerically. We show that the interplay between shear- and
chirality-induced angular velocities, combined with the effects due to particle
self-propulsion and steric particle-wall interactions, lead to an interesting
range of effects, including pinning, off-centered and near-wall accumulation of
swimmers within the channel. This is further accompanied by the linear
stability analysis of swimmers, used to explain the probabilistic results. We
discuss the qualitative differences of probabilistic results that emerge due to
the different regimes of rotational dynamics of swimmers in channel flow,
particularly the shear-trapping/-escaping of prolate/oblate swimmers and the
difference in latitudes of fixed points associated with each swimmer shape. Our
results point to possible mechanisms for flow-driven separation of active
spheroidal particles based on their chirality strength.
