[P2-59] A Discrete Tetris model showing two flow regimes for hard particles exiting a hopper with an adjustable obstacle
Placing an obstacle near the orifice of a hopper has been shown experimentally and numerically to locally enhance the flow rate for hard particles leaving the hopper under gravity. A flow rate difference between its value near the obstacle and its maximal value without an obstacle can explain this phenomenon with minimal dynamics involved. When the obstacle sits close to the hopper orifice, the flow rate near the obstacle is smaller than the maximal value, which corresponds to a fluidized flow regime. On the other hand, when the obstacle is placed further from the orifice, the flow rate near the obstacle becomes larger than the maximal value and a clogging flow regime appears. In this study, we employ a Tetris model in 2D discretized space and successfully demonstrate the two flow regimes. Without creating overlap between any objects in the system, our model sequentially relocates one particle at a time into its von Neumann or Moore neighborhood closer to the hopper orifice. Our results show that in the fluidized regime, where flow rate is low, the Moore protocol, which allows higher freedom to move particles, gives higher flow rate than the von Neumann protocol. The trend reverses in the clogging regime, where higher freedom to move particles renders lower flow rate.