Settling Velocity Calculator

Ferguson & Church (2004) equation for particle settling velocity.

Unit System

Material Presets

Density of Water (kg/m³)

Density of Solid (kg/m³)

Particle Diameter (mm)

Molecular Viscosity (Pa·s)

C₁ (Stokes' constant)

C₂ (Turbulence constant)

About the Equation

The Ferguson & Church (2004) equation calculates the settling velocity of particles in a fluid. The submerged specific gravity \( R \) is defined as:

\[ R = \frac{\rho_{\text{solid}} - \rho_{\text{water}}}{\rho_{\text{water}}} \]

The settling velocity \( w \) is given by:

\[ w = \frac{R g D^2}{C_1 \nu + \sqrt{0.75 C_2 R g D^3}} \]

where \( \nu = \frac{\mu}{\rho_{\text{water}}} \) is the kinematic viscosity.

Default values:
- Quartz in water: \( \rho_{\text{water}} = 998 \, \text{kg/m}^3 \), \( \rho_{\text{solid}} = 2650 \, \text{kg/m}^3 \), \( \mu = 1.002 \times 10^{-3} \, \text{Pa·s} \), \( C_1 = 20 \), \( C_2 = 1.0 \)
- Natural sand: \( C_1 = 24 \), \( C_2 = 1.2 \)

Ready for Analysis

Adjust presets or parameters, then click "Open Result Window"