Scaling exponents for energy transport and dissipation in binary vibro-fluidized granular beds

A binary three-dimensional highly fluidized vibrated granular bed has been investigated for the first time using positron emission particle tracking. Packing fraction distributions and granular temperature profiles are calculated for each species and the response to changes in the amplitude of vibration and the number of grains are determined. It is found that the binary system, though supporting two separate granular temperature profiles, responds to changes in vibration velocity in a broadly similar fashion to a monosized granular bed. This assessment is supported by an analysis of the steady-state energy input/dissipation rate balance equation, which contains terms describing the collisional dissipation between like and unlike grains. However, this theory also suggests that if one fraction dominates over another then the two phases could show different scaling relationships between the granular temperature of each phase and the base peak velocity. (C) 2003 American Institute of Physics.