Dataset 2/2 of experiments on particle segregation in confined and non-uniform granular shearing flows

This dataset contains the experimental measurements used in the study “Complex segregation patterns in confined nonuniform granular shearing flows” by Santiago Caro, Riccardo Artoni, Patrick Richard, Michele Larcher, and James T. Jenkins (2026). The data were obtained from annular shear cell experiments designed to investigate size segregation in dense bidisperse granular flows under confined and nonuniform shear conditions. The experiments explore how segregation dynamics depend on mixture properties and flow kinematics in confined granular systems. Experimental setup The experiments were conducted in a bounded annular shear cell consisting of two transparent coaxial cylinders made of polymethyl methacrylate. The inner and outer cylinders have diameters of 200 mm and 300 mm respectively, creating an annular region where the granular material flows. The granular material is confined between: a bumpy rotating bottom plate, which imposes shear on the system, and a bumpy top loading plate, free to move vertically and applying a constant confining load. The bottom plate rotates at a constant angular velocity of Ω = 18.5 rpm, producing a dense granular flow characterized by nonuniform shearing, with a localized shear band near the bottom and a creep region above. Granular materials The experiments use bidisperse mixtures of polyoxymethylene (POM) spherical particles with density ρ = 1.41 g/cm³. Particle diameters of 4 mm, 6 mm, and 8 mm were used to generate different size ratios. The total mass of particles in the cell was 2500 g, producing a granular layer approximately 25 particle diameters deep. Experimental Conditions A total of six bidisperse mixtures were tested by varying the particle size ratio and the mass fraction between large and small particles.