A numerical study of dynamics in thin hopper flow and granular jet
Wang Meng-Ke1, 2, Yang Guang-Hui1, 2, Zhang Sheng1, 2, Cai Han-Jie1, 2, Lin Ping1, 2, †, Chen Liang-Wen1, 2, Yang Lei1, 2
       

Spatial vector field plot of time-averaged vz in the yz plane inside the hopper with the slot width (a) D = 5d, (b) D = 10d, (c) D = 20d, (d) D = 30d. The arrow heads indicate the velocity direction. The length of arrows and the color scale indicate the velocity magnitude.