(378d) Cohesive Particle Flows: On the Relevance of Cohesive Energy Vs. Cohesive Force Descriptions

Particle cohesion arising van der Waals force, liquid bridges, etc. is known to vary as a function of separation distance. Although the incorporation of such a dependency is straightforward to accommodate in DEM simulations, the same is not true for continuum models since individual particles are not tracked. To overcome this challenge, previous models have used either (i) a force balance at particle contact or (ii) cohesive energy â?? the integration of the force profile with distance â?? as a basis for incorporating the effects of cohesion. This force vs. energy conundrum is also evidenced by the various dimensionless numbers used to describe various systems: cohesive force/gravitational force (Bond number), cohesive energy/kinetic energy, etc. In this talk, we consider a number of systems to illustrate the appropriateness of force-based vs. energy-based descriptions in a variety of circumstances.