Environmental Engineering Reference
In-Depth Information
The following double
all
command on the
~ confined
arraydeliversa1ifthe
aquifer is unconfined. For the remaining situations, in which the aquifer is neither
confined nor unconfined, the corresponding message is given in the nested
else
block.
The
any
command is applied in the last four lines. It asks if the condition is true
for any entry of the matrix
phi
<
0
. Any user in doubt may examine that for each
matrix
A
the expression
A
<
0
is a matrix too! If the head value, representing the
height of the piezometer level table above the aquifer base, becomes less or equal
zero, the aquifer is fallen dry. Is that true in any part of the chosen region, the
corresponding message is given in the command window. The final command
changes all negative head values (as they are impossible) to zero.
The commands outlined above are part of the
“gw_flow.m”
file, which
is included in the accompanying software. The groundwater baseflow and well
example is extended in Chap. 15.
Exercise 14.1. Vary parameters and examine in which parts the aquifer is confined
and unconfined, and when the aquifer falls dry!
14.4 MATLAB
2D Graphics
®
Based on mesh data several output commands for 2D and 3D meshes are available
in MATLAB
. Some of these (
contourf
and
surf
) have already been introduced
in the previous sub-chapters. They will be demonstrated here by extending the M-
file developed in this chapter until this point. First a graphic option is introduced in
the specification part of the M-file:
®
% Graphical output options
gsurfh = 1;
% piezometric head surface plot
The user controls the graphical output by the
gsurfh
parameter. At the end of
the previous version of the M-file add the plot commands:
%----------------------------------graphical output----------------
if
gsurfh
figure; surf (x,y,h);
% surface
end
If the graphics control parameter is nonzero, the figure editor is opened and a
surface of the head values is plotted.
As another extension of the M-file, two further graphics options are added:
gcontf = 20;
% no. filled contour lines (=0: none)
gquiv = 1;
% arrow field plot
which are connected to additional output commands at the end of the file:
