  Hydrodynamic interaction strongly influences the collective behavior of the
microswimmers. With this work, we study the behavior of two hydrodynamically
interacting self-propelled chiral swimmers in the low Reynolds number regime,
considering both the near and far-field interactions. We use the chiral
squirmer model, a spherically shaped body with non-axisymmetric surface slip
velocity, which generalizes the well-known squirmer model. We calculate the
lubrication force between the swimmers when they are very close to each other.
By varying the slip coefficients and the initial configuration of the swimmers,
we investigate their hydrodynamic behavior. In the presence of lubrication
force, the swimmers either repel each other or exhibit bounded motion where the
distance between the swimmers alters periodically. The lubrication force favors
the bounded motion in some parameter regime. This study is helpful to
understand the collective behavior of dense suspension of ciliated
microorganisms and artificial swimmers.
