Incipient motion of sediments in oscillatory flows of pseudoplastic fluids: Preliminary results

Abstract

Preliminary results of an experimental study on the incipient motion of granular, non-cohesive particles in a laminar oscillatory flow of water and power law fluids are presented in this paper. The threshold condition is defined in terms of two dimensionless variables, one (ψ ) representing the ratio between Coulombic and drag forces acting on the particles, and another χn) that involves the quotient of the particle diameter and a scale of the boundary layer thickness, a modified Reynolds number of the particle, and a function of the flow behaviour index of the fluid. A relation between ψ and χnwas obtained that shows good agreement with the experimental data.