Review on Size Segregation in Vibrated Granular Media

Abstract

Size segregation phenomena in granular media subjected to vibration are reviewed. Various explanatory mechanisms proposed in the literature are presented, including convection, void-filling, arching effect, condensation, granular temperature gradients, and entropic-like forces. While each mechanism provides valuable insights, these explanations remain qualitatively limited in scope and applicability. Studies on quasi-two-dimensional (2D) setups are also discussed, which, despite their simplicity, exhibit various structural formations including crystallization, segregation patterns, and quasicrystals. Recent findings on reducing segregation by increasing the volume fraction of small particles are described. Granular segregation remains an active research area with fundamental mechanisms still unestablished, despite its practical importance across various industries including food processing, pharmaceuticals, construction materials, and cosmetics.