The discharge of granular materials from a silo subject to vertical vibration was studied in cylindrical silos. A hemispherical bottom silo with five different angles of outlets was proposed. The effects of the stirring shaft angular velocity, the dimensionless depth of granular materials, and the discharge exit angle on the discharge in the silo were compared. An enhancement factor was proposed to evaluate the effect of vertical vibration on improving the discharge of the granular materials. A positive correlation was found between the discharge rate and dimensionless depth in the low range of dimensionless depth. The vibration had an inhibitory effect on the discharge when the vibration frequency of the silo was lower than 30 Hz or the amplitude was higher than 0.11. The granular material had the highest discharge rate when the outlet was at 54 degrees from the vertical direction under both non-vibration and vibration conditions. (C) 2020 Elsevier B.V. All rights reserved.