D-R-A-F-T
coefficient for the bed source/sink terms, kg/(m3-sec)
α2
=
The general characteristics of the governing equation are best understood by
performing dimensionless analysis of the equation to develop the characteristics for
certain conditions. To facilitate the analysis the following scaling factors are applied
C
=
C0
c'
∆t
T
=
t'
U
=
V u'
V
=
V v'
X
=
L x'
Y
=
L y'
Dx
=
Dr Dx'
Dy
=
Dr Dy'
The source/sink term coefficients α1 and α2 vary for sand and clay and whether
deposition or erosion is occurring. These conditions will be addressed separately
later. For the first analysis, sand deposition will be assumed.
Transform The Sand Deposition Equation
For sand deposition the source sink terms take on the form
Equation 30
(C - G p )Vs
S = α1C + α 2 = -
Lde D
where
transport potential from Ackers-White , kg/m3
Gp
=
Vs
=
sediment fall velocity, m/s
=
scale length factor deposition, dimensionless
Lde
D
=
water depth, m
For this condition, the following scaling factors are used
=
Gp
Co Gp'
D
=
H D'
=
Vs
Ws Vs'
From the application of these scaling factors we get
Equation 31
44 Advanced Techniques
Users Guide To SED2D-WES
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