Resolving the angular velocity of two-dimensional particle interactions induced within a rotary tumbler

A horizontally oriented cylindrical tumbler, filled at variable depth with a monoplane of uniform cylindrical media, was rotated at various constant speeds. Resultant motion was captured using a high-speed camera. The images were post-processed with particle tracking velocimetry and image correlation algorithms in order to estimate each particle’s translational and rotational velocity. The particle interactions were then characterized into distance groups based on non-dimensional flow characteristics, where similarities were found with transitions between slip/no-slip and rotation/no-rotation conditions. The results of the particle interactions show rotational chains as analogous to translational force chains. The interactions demonstrated that occurrences of no-slip, no-rotation behavior correspond to areas of confined translational motion. No-slip rotation behavior was lower in areas of high interaction and higher in developing flow areas. Graphical Abstract