D-R-A-F-T
Advanced Techniques
Analytical Test Cases
Non-dimensional Analysis of Governing Equation
This section reviews the numerical formulation used in SED2D-WES and presents
an analysis of the use of the appropriate numerical coefficients for a given numerical
mesh and simulation design. The numerical mesh and hydrodynamic solution
present certain dimensional characteristics to the governing equations of sediment
transport. For a given mesh and hydrodynamic solution (RMA-2) the transport
model will have certain numerical restrictions that will limit the ability of the
program to provide accurate solutions. A clear understanding of these limitations
can lead to either a redesign of the mesh and hydrodynamic simulation or guidance
in the compromises necessary in the numerical coefficients in SED2D-WES.
Transforming The CD Equation
Recall that the convection-diffusion equation (Equation 1), a.k.a. CD equation,
solved by SED2D is of the basic form:
∂C
∂C ∂
∂C ∂
∂C
∂C
- α1C - α 2 = 0
+u
+v
-
-
Dy
Dx
∂y ∂x
∂t
∂x
∂x ∂y
∂y
where
depth-averaged sediment concentration, kg/m3
C
=
T
=
time, sec
x,y
=
horizontal Cartesian coordinates, meters
u,v
=
current velocity components in the x,y directions, m/sec
Dx,Dy
=
α1
=
coefficient for the bed source/sink term, 1/sec
Advanced Techniques 43
Users Guide To SED2D-WES
Previous Page
