The video shows a granular flow through a channel of length 15cm, width 6.3cm and height 2.1cm. Gravitational acceleration acts towards the bottom. On the left end spherical particles of 1mm diameter are generated with an inflow velocity of 1m/s. An obstacle obstructs the flow 3cm downstream. It has a D-shaped cross section, is 2cm long and wide, extends to the full height of the channel, and is placed directly in the middle of the channel. The setup was simulated for 10s simulation time with time steps of length 10us. In each time step 10 iterations of a parallel non-smooth contact dynamics (NSCD) method were performed. The simulation ran for 50 minutes on 32 nodes of the Emmy cluster at the regional computing centre in Erlangen (RRZE). To properly resolve the dynamics visual scene descriptions were written to disk with a rate of 300 frames per second. The final video is slowed down by a factor of 10. The average maximum penetration in 50 samples was 1.8% of the particle diameter. The formation of a steady-state flow with minor local fluctuations as well as the formation of recirculation regions behind the obstacle can be observed
