4/98

SED2D-WES Version 4.3 Beta

x=

primary flow direction, m

v=

flow velocity in y - direction, m/sec

y=

direction perpendicular to x , m

effective diffusion coefficient in x-direction, m2/sec

Dx =

effective diffusion coefficient in y-direction, m2/sec

Dy =

α1 =

a coefficient for the source term, 1/sec

α2 =

This equation is then cast into the finite element form using quadratic shape functions, N ,

C

$+

$

$

$

$

Nj

Nj

NE

NL

C

C

C

- α1 C

∑ ∫∫ N j Q + u

+v

+

dxdy + ∑ ∫ N j qs dζ = 0

(2)

Dx

Dy

i

ne =1 Dne

y

x

y

x

x

y

i =1 ζ

where

NE =

total number of elements

N=

the quadratic shape functions

( C t) + α2 for the transient problem

$

Q=

$

C=

the approximate concentration in an element as evaluated from shape functions and nodal point

values of C

NL =

total number of boundary segments

ζ =

the local coordinate

qs =

flux from source on boundary i

i

The transient equation is expressed as

8