A two-phase flow model of sediment transport: transition from bedload to suspended load

摘要

The transport of dense particles by a turbulent flow depends on twodimensionless numbers. Depending on the ratio of the shear velocity of the flowto the settling velocity of the particles (or the Rouse number), sedimenttransport takes place in a thin layer localized at the surface of the sedimentbed (bedload) or over the whole water depth (suspended load). Moreover,depending on the sedimentation Reynolds number, the bedload layer is embeddedin the viscous sublayer or is larger. We propose here a two-phase flow modelable to describe both viscous and turbulent shear flows. Particle migration isdescribed as resulting from normal stresses, but is limited by turbulent mixingand shear-induced diffusion of particles. Using this framework, wetheoretically investigate the transition between bedload and suspended load.