Finite Element Techniques for Fluid Flow

FLOW THROUGH POROUS MEDIA 229

techniques. After each At we can iterate on the equations until

h = h to some desired accuracy.

The main disadvantage of Dupuit's approximation is that it fails

to take into account a free seepage surface of the type shown in

Figure 6.13. In other words we are considering that h = h

w

for the

well shown in the figure. The error involved in this assumption is

generally small and confined to a short distance from the well.

Figure 6.13 Free seepage surface

For the case of horizontal aquifer bottom and steady state flow,

equation (6.70) simplifies to

or

£{*»£Κ{^}-* ™

Equation (6.74) can be solved directly in terms o ...