Experimental study on the effect of surface roughness of the intruder on the Brazil nut problem in a vertically vibrated bed.

This study experimentally investigates the influence of intruder surface roughness in the Brazil nut effect in a quasi-two-dimensional vertical vibration granular bed. The intruder dynamics are determined using a particle-tracking method. The results show that surface roughness has a crucial role in the intruder rise dynamics; a rougher intruder has more difficulty rising in the bed because of higher kinetic energy dissipation. This study determined that penetration length and drag length are reduced and drag is enhanced as intruder surface roughness increases. The exponential decay of the penetration length with vibration frequency is shown. The results also show that at higher dimensionless vibration acceleration and lower vibration frequency the variation in rise time between smooth and rough intruders is negligible.