  Two-dimensional granular discharge flow driven by gravity under the influence
of an obstacle is experimentally investigated. A horizontal exit of width $W$
is opened at the bottom of vertical Hele-Shaw cell filled with stainless-steel
particles to start the discharge flow. In this experiment, a circular obstacle
is placed in front of the exit. Thus, the distance between the exit and
obstacle $L$ is also an important parameter. During the discharge,
granular-flow state is acquired by a high-speed camera. The bulk discharge-flow
rate is also measured by load cell sensors. The obtained high-speed-image data
are analyzed to clarify the particle-level granular-flow dynamics. Using the
measured data, we find that the obstacle above the exit affects the
granular-flow field. Specifically, the existence of obstacle results in large
horizontal granular temperature and small packing fraction. This tendency
becomes significant when $L$ is smaller than approximately 6$D_g$ when $W
\simeq 4 D_g$, where $D_g$ is diameter of particles.
