  Many disordered systems experience a transition from a fluid-like state to a
solid-like state following a sudden arrest in dynamics called jamming. In
contrast to jamming in spatially homogeneous systems, jamming in hoppers occurs
under extremely inhomogeneous conditions as the gravity-driven flow of grains
enclosed by rigid walls converges towards a small opening. In this work, we
study velocity fluctuations in a collisional flow near jamming using
event-driven simulations. The average flow in a hopper geometry is known to
have strong gradients, especially near the walls and the orifice. We find, in
addition, a spatially heterogeneous distribution of fluctuations, most striking
in the velocity autocorrelation relaxation times. At high flow rates, the flow
at the center has lower kinetic temperatures and longer autocorrelation times
than at the boundary. Remarkably, however, this trend reverses itself as the
flow rate slows, with fluctuations relaxing more slowly at the boundaries
though the kinetic temperatures remain high in that region. The slowing down of
the dynamics is accompanied by increasing non-Gaussianity in the velocity
distributions, which also have large spatial variations.
