Experimental determination of temperature profiles in a sheared granular bed containing two and three sizes of particles

An experiment to measure granular temperature in a sheared low density granular bed containing a range of sizes of particles has been performed. Using positron emission particle tracking, a single particle was tracked from different size phases. From the coordinate data, the second moment of the velocity fluctuations about the mean flow in each direction was determined. It was found that the larger particles are "hotter" and that most of the energy is contained in the θ (shearing) direction fluctuations. Evidencewas found for Knudsen layer and higher order Burnett effects, suggesting extensions of theNavier-Stokes approaches are necessary to describe heat transport in polydisperse systems.