Erosion, Sedimentation, and Geomorphology
Interparticle collision of natural sediment grains in water
Article first published online: 9 JUL 2010
Copyright 2001 by the American Geophysical Union.
Water Resources Research
Volume 37, Issue 9, pages 2377–2391, September 2001
How to Cite
2001), Interparticle collision of natural sediment grains in water, Water Resour. Res., 37(9), 2377–2391, doi:10.1029/2001WR000531., , , and (
- Issue published online: 9 JUL 2010
- Article first published online: 9 JUL 2010
- Manuscript Accepted: 22 MAR 2001
- Manuscript Received: 30 AUG 1999
Elastohydrodynamic theory and measurements of particle impacts on an inclined glass plane in water are used to investigate the mechanics of interparticle collisions in sediment-transporting flows. A collision Stokes number is proposed as a measure of the momentum of an interparticle collision versus the viscous pressure force in the interstitial gap between colliding particles. The viscous pressure force opposes motion of the particles on approach and rebound. A Stokes number of between 39 and 105 is estimated as the critical range below which particle impacts are completely viscously damped and above which impacts are partially elastic. The critical Stokes number is shown to roughly coincide with the Bagnold number transition between macroviscous and grain inertial debris flows and the transition between damped and partially elastic bed load transport saltation impacts. The nonspherical nature of natural particles significantly alters the motion of the center of mass after a partially elastic collision. The normal to the point of contact between the particles does not necessarily go through the center of mass. Thus normal rebound of the center of mass may not occur. A model of particle motion after rebound for particles of arbitrary shape, conserving both linear and angular momentum, is proposed.