Enhanced flow rate by the concentration mechanism of Tetris particles when discharged from a hopper with an obstacle

We apply a holistic two-dimensional (2D) Tetris-like model, where particles move based on prescribed rules, to investigate the flow rate enhancement from hopper. This phenomenon was originally reported in literature as feature of placing an obstacle at optimal location near exit hopper discharging athermal granular under gravity. find that this is limited system sufficiently many particles. In addition waiting room effect, another mechanism able explain and create concentration their way reaching after passing obstacle. elucidate by decomposing into its constituent variables: local area packing fraction ${\ensuremath{\phi}}_{l}^{E}$ averaged particle velocity ${v}_{y}^{E}$ exit. comparison case without obstacle, our results show optimally placed can net relatively weakly driven particles, caused exit-bottleneck coupling if ${\ensuremath{\phi}}_{l}^{E}>{\ensuremath{\phi}}_{o}^{c}$, ${\ensuremath{\phi}}_{o}^{c}$ characteristic marking transition fast slow regimes Tetris Utilizing artificially guiding central sparse space or narrowing angle we manmade peak strongly initially exhibit no peak. Additionally, enhanced be maximized shape, acceleration toward exit, geometry