Modeling entrainment of sedimentary particles by wind and water: A generalized approach

For long‐standing theoretical reasons, it is often asserted that the threshold shear stress for entrainment of sedimentary particles (τ*t = ρfu*t2, made dimensionless as A = ρfu*t2/((ρp − ρf)gd)) has a universal relationship with the particle Reynolds number (Re*t = u*td/ν), where u*t is the threshold friction velocity, ρf is the fluid density, ρp is the density of the particles, d is the particle diameter, g is the gravitational acceleration and ν is the kinematic viscosity of the fluid. However, experimental plots of A(Re*t) for sediment entrainment in air and water show two major differences: (1) For large Re*t, the values of A in water are, in general, a few times larger than those in air, and (2) when Re*t