Abstract: A two-dimensional sandpile avalanche model of silo-timing is proposed. By using the celluar automata method, we perform the computer simulation for this model. The results show that there is a periodic oscillation for the flow of entrance granular in the process of granular avalanche. The total time of avalanche increases linearly with the size of hole. The beating of avalanche occurs as the entrance is a special place and changes periodically with granular height.

Key words: silo- timing, two- dimensional numerical simulation, oscillating period