2. Sedimentation

2.1 Motion of a solid particle in a stationary fluid

Consider a spherical particle, with density ρ _g , diameter d _g , sedimentation velocity U, relative to the fluid of density ρ _f and viscosity η in which it settles.

We define a grain Reynolds criterion : $R{e}_g=\frac{{\rho }_{f}U{d}_g}{\eta }$

The grain is slowed down in its movement by the fluid and a drag force F appears which depends on...