D-R-A-F-T
⎧
D
Cd
⎪ V
⎪
s
⎪
Tc = larger of ⎨or
⎪
⎪
⎪DT
⎩
where
=
characteristic time
tc
Cd
=
coefficient for deposition
D
=
flow depth
Vs
=
fall velocity of a sediment particle
DT
=
computation time interval
In the case of scour, there are no simple parameters to employ. The following
expression is used.
Equation 13
⎧ D
⎪Ce u
⎪
⎪
tc is larger of ⎨or
⎪
⎪
⎪DT
⎩
where
Ce
=
coefficient for entrainment
V
=
flow speed
Clay Transport: Option 1
For clay transport, option 1 is the default. Deposition rates of clay beds are
calculated with the equations of Krone (1962).
Equation 14 a and b
⎧ Vs ⎛
τ ⎞
⎪- C⎜1 - ⎟ forC < Cc ,τ < τ d
⎟
⎜
⎪ D ⎝ τd ⎠
S =⎨
⎪- Vk C 7 3 ⎛1 - τ ⎞ forC > C ,τ < τ
⎜ τ ⎟
⎜
⎟
⎪ D
c
d
d⎠
⎝
⎩
where
τ
=
bed shear stress
τd
=
critical shear stress for deposition
Cc
=
critical concentration = 300 mg/l.
12 Conceptual Program Design
Users Guide To SED2D-WES
Previous Page
