Shields parameter

The Shields parameter, also called the shields criterion or shields number, is a nondimensional number used to calculate the initiation of motion of sediment in flowing water. It is a nondimensionalization of a shear stress, and is typically denoted $\tau *$ or $\theta$. It is given by:

$\tau *=\theta ={\frac {\tau }{(\rho _{s}-\rho )gD}}$

where

$\tau$ is a dimensional shear stress

$\rho _{s}$ is the density of the sediment

$\rho$ is the density of water

$g$ is acceleration due to gravity

$D$ is mean particle diameter of the sediment

References

. doi:10.1061/(ASCE)0733-9429(2006)132:10(1097). {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)