GRAVITY GRANULAR FLOWS OF SLIGHTLY FRICTIONAL PARTICLES DOWN AN INCLINED BUMPY CHUTE

Gravity-driven granular flow of slightly frictional particles down an inclined, bumpy chute is studied. A modified kinetic model which inclu des the frictional energy loss effects is used, and the boundary condi tions for a bumpy wall with small friction are derived by ensuring the balance of momentum and energy. At the free surface, the condition of vanishing of the solid volume fraction is used. The mean velocity, th e fluctuation kinetic energy and the solid volume fraction profiles ar e evaluated. It is shown that steady granular gravity flow down a bump y frictional chute could be achieved at arbitrary inclination angles. The computational results also show that the slip velocity may vary co nsiderably depending on the granular layer height, the surface boundar y roughness, the friction coefficient and the inclination angles. The model predictions are compared with the existing experimental and simu lation data, and good agreement is observed. In particular, the model can well predicate the features of the variation of solid volume fract ion and fluctuation energy profiles for different particle-wall fricti on coefficients and wall roughnesses.