  Simulations employing the continuum model of Gao et al. [Phy. Rev. Fluids, 2
093302 (2017)] are used to study the transport of an object in a closed
two-dimensional container by a dense suspension of contractile active agents.
For parameters that generally yield nematic alignment, the initial flow and
object motion is typically characterized by chaotically interacting m = +/- 1/2
defects in its nematic structure, which form in oppositely signed pairs or on
the container wall or on the object. Those that form on the object also make an
oppositely-signed contribution to the mo nematic structure associated with the
object. However, in many cases, the chaotic flow does not persist. It instead
ends up in one of two states, which are studied in detail for a circular object
in a circular container. One is a fixed point, associated with a mo=+1 object
with radial nematic ordering. The suspension flows but with the object
stationary near the container wall. A sharply-aligned nematic model confirms
that its position is maintained by a (nearly) hydrostatic balance and that a
related circumferential mo = +1 configuration, which is not observed, would
indeed be unstable. The second terminal behavior, which can occur for the same
physical parameters as the fixed-point behavior, is associated with a mo=+1
object. It is a limit-cycle oscillation in which the object cyclically
traverses the container, spawning transient m = - 1/2 defect pairs each
half-cycle. Both of these configurations are analyzed in detail, and are
potential related to simple biological tasks. It is shown that they also occur
in square and elliptical containers, with the ellipse displaying a particularly
rich phenomenology that includes switching between them.
