[P2-58] Studying the kinetics of a self-propelled cruiser in 2D granular media under gravity
Experimentally and numerically, it has been shown that placing an obstacle near the orifice of a hopper can locally enhance the flow rate for hard discs leaving the hopper under gravity. Besides, the enhanced flow rate happens regardless the interparticle friction, the obstacle geometry, or particle dispersity. In this study, we propose a Tetris model to further clarify the physics behind this phenomenon. The model sequentially moves one particle at a time towards the hopper orifice, governed by Gaussian displacement functions. A particle can move as long as the movement creates no overlap between the particle and the others, the obstacle, or the boundaries of the hopper. Our model reduces the dynamics in the system to its minimal and allows no interparticle collaborative motion due to Newtonian dynamics. Using this model, we successfully reproduce the locally enhanced flow rate, which can be explained by a flow rate difference between its value near the obstacle and its maximal value without an obstacle. Our results show that the flow rate difference is the fundamental reason causing this phenomenon - universal with minimal dynamics involved.