Geoscience Reference
In-Depth Information
Fig. 8.21 Drawing of
the original
experimental
set-up as
presented by
Darcy (1856).
operator. With subscripts representing the vector components, this is also often written
as
k
∂
h
q
i
=−
(8.20)
∂
x
i
where
x
i
represents
x
,
y
and
z
for
i
ρ
at a pressure
p
in an infinitesimal control volume, the forces that drive the flow are (per
unit volume) the pressure gradient
=
1, 2 and 3, respectively. For a fluid of density
g
k
), if
z
is the vertical coordinate
so that
k
is the unit vector in the vertical direction. Therefore, whenever the fluid density
∇
p
and gravity (
ρ
