Geoscience Reference
In-Depth Information
5.2.1.3 Treatments for flow at channel confluences
and splits
Fig. 5.8 shows a typical network of channels connected with confluences, splits, and
hydraulic structures. To compute the steady flow in such a channel network, external
boundary conditions at inlets and outlets and internal boundary conditions at channel
confluences, splits, and hydraulic structures have to be imposed. The imposition of
external boundary conditions of flow is introduced in Section 5.1.1.2, and the handling
of hydraulic structures is discussed in Section 5.2.2.4. Treating channel confluences
and splits is discussed here.
Figure 5.8
Sketch of a channel network.
Channel confluences
A confluence of two channels is depicted in Fig. 5.9, in which cross-sections 1 and 2
are placed at the ends of the upstream channels (denoted as 1 and 2), and cross-section
3 is at the beginning of the downstream channel (denoted as 3). The flow discharges at
cross-sections 1, 2, and 3 are denoted as
Q
1
,
Q
2
, and
Q
3
, respectively. The continuity
equation at the confluence reads
Q
3
=
Q
1
+
Q
2
(5.48)
Figure 5.9
Configuration of channel confluence.
