The jamming of particles during the silo discharge is a long-standing problem. The silo with a curved hopper can effectively prevent jamming. In this work, discrete element method was used to study the effect of contraction rate on the discharge flow characteristics in the silo with a curved hopper. Froude number was adopted to evaluate the flowability of the silo. It was found that a smaller contraction rate is propitious to granular flows. Particularly, the contraction rate was found to have a distinguishing point. Meanwhile, the effectiveness of the distinguishing point is experimentally confirmed. Moreover, the discharge rates of the curved hopper and the conical hopper under the same conditions were compared. Finally, the mathematical model between the contraction rate and Froude number was established. Understanding of the flow mechanism is useful to the design, scale-up and optimization of the silo with a curved hopper and similar structural devices. (C) 2019 Elsevier B.V. All rights reserved.