Sediment transport

Generalities

The calculation of sediment exchanges involves three steps:

  • Calculating an equilibrium concentration C_{eq} according to a proposed law;
  • Calculating an adaptation time following of Han’s formulat_A=\beta\frac{Ru*}{VW} or Hazen’s formula: t_A=\beta\frac{R}{W} where W is the fall velocity;
  • Calculation of the exchange termE=\frac {\alpha C_{eq}-C }{t_A} ;
    where \alpha and \beta are dimensionless parameters.

The fall rate is calculated according to Zanke’s formula:

W=1.1*10\frac{\nu}{d}\left(\sqrt{1+\frac{0.01 g (\rho_S/\rho-1)d^3}{\nu^2}}-1\right)


This law is equal to Stokes’ law for small diameters, and Newton’s law for larger particles.