BEHAVIOR OF VIBRATING BEDS OF IRREGULAR PARTICLES

This paper examines the behaviour of vibrating beds of irregular particles through measurements of air pressure beneath, and in some cases along one side of, the particle bed. Two kinds of irregular particles (tenryu sand and alumina particles) were used, and two size ranges of glass beads. Glass beads were used to contrast the bed behaviour of the irregular particles to that of similar-sized spherical particles. Experimental data were compared with predictions of the compressible gas model, the best available in the literature. The beds of irregular particles did not comply well with the model predictions unless viscoelasticity was taken into account in the model. Air pressure measurements along one side of the bed revealed the occurrence of tensile stress within particle beds. The tensile stress and an unusual air pressure reversal may be related through the change in particle bed voidage.