Civil Engineering Reference
In-Depth Information
Q
1
=100
(sink)
1
2
3
4
kA=4
L=1
kA=3
L=1
kA=2
L=1
1
2
3
H
2
= -10
H
4
=10
nels nn np_types
3 4 3
prop(ka)
4.0 3.0 2.0
etype
1 2 3
ell
1.0 1.0 1.0
g_num
1 2 2 3 3 4
loaded_nodes,(k,loads(k),i=1,loaded_nodes)
1
1 -100.0
fixed_freedoms,(node(i),value(i),i=1,fixed_freedoms)
2
2 -10.0 4 10.0
Figure 7.1 Mesh and data for first Program 7.1 example
Figure 7.1 shows a string of three elements attached end to end. Each element has the
same length, but different permeability properties. In this context, the property applied to
each element is
kA
(analogous to
EA
in Program 4.1), namely the product of the perme-
ability and the cross-sectional area of each element. A fixed steady outflow or “sink” of
−
100.0 (negative sign denotes outflow) is applied at node 1, and the total head is fixed to
−
10.0 and 10.0 at nodes 2 and 4 respectively. The data involves reading the number of
elements
nels
, the number of nodes
nn
, and the number of property types
np types
.
In this case there are 3 property types, one for each element, so with
np types>1
the
etype
data is read next, indicating that element 1 has a
kA
of 4.0, element 2 has a
kA
of
3.0, and so on. The element lengths
ell
are read, followed by the node numbers of each
element
g num
. In the case of a string of elements such as this, the
g num
data is quite
There are 4 equations and the skyline storage is 7
Node Total Head Flow rate
1 -0.3500E+02 -0.1000E+03
2 -0.1000E+02 0.7600E+02
3 -0.2000E+01 0.3553E-14
4 0.1000E+02 0.2400E+02
Inflow Outflow
0.1000E+03
-0.1000E+03
Figure 7.2 Results from first Program 7.1 example
