# Settling velocity

## Description

The terminal velocity of a particle which is falling in the viscous fluid under its own weight due to gravity.

Generally, for small particles (laminar approximation), it can be calculated with Stokes’ Law. For larger particles (turbulent particle Reynolds numbers), fall velocity is calculated with the turbulent drag law.

Analytically combination of the expression for Stokes flow and the turbulent drag law, into a single equation that works for all sizes of sediment, resulted to a formula that successfully tested against the data as well as the empirically curves of settling velocity .

C1 and C2 are constants related to the shape and smoothness of the grains.

## Variables

w_{s} | Sediment settling velocity (m/s) |

R | Reynolds number (dimensionless) |

g | Standard gravity |

D | Mean sediment diameter (m) |

v | kinematic viscosity of water (m^{2}/s) |

C_{1} | Constants related to the shape and smoothness of the grains (dimensionless) |

C_{2} | Constants related to the shape and smoothness of the grains (dimensionless) |