Common macroscopic framework for cohesion across microscopic sources

Determine whether a common macroscopic framework can capture the effects of interparticle cohesion on the collapse and final morphology of granular columns irrespective of the microscopic source of cohesion at the particle scale (e.g., capillary bridges in wet grains or polymer coatings on glass beads).

Background

The introduction surveys prior studies on granular column collapse and notes that cohesion alters rheology and deposit morphology, with different microscopic mechanisms (capillary bridges, polymer coatings, van der Waals, electrostatics) potentially acting simultaneously. While many works investigate specific sources and geometries (often quasi-2D), a unified macroscopic description that applies regardless of the microscopic origin has been lacking.

This study proposes and tests a dimensionless cohesive number Co, based on bulk yield strength and particle weight, aiming to rationalize cohesive effects across wet grains in the pendular state and polymer-coated beads in both axisymmetric (3D) and channelized (2D) collapses. The quoted passage explicitly flags the uncertainty about the existence of such a common framework.