2-D numerical models - Computational River Dynamics - page 280

flow field and bed topography are interpolated from the old mesh to the new mesh.
Then the computations of flow, sediment transport, bed change, and bank erosion are
continued on the new mesh at the next time step.
Fig. 6.19 shows the channel bank migration process simulated by Duan et al . (2001)
using a depth-averaged 2-D model, which generally agrees with the experimental data
measured by Nagata et al . (2000). Fig. 6.20 shows a simulation example performed
by Duan et al ., in which a slightly curved channel develops into a strongly meandering
channel. The results are plausible.

Figure 6.19 Simulated and measured channel migration processes (Duan et al ., 2001).

Figure 6.20 Simulated channel meandering process (Duan et al ., 2001).

6.4 WIDTH-AVERAGED 2-D MODEL OF FLOW
AND SEDIMENT TRANSPORT

6.4.1 Width-averaged 2-D hydrodynamic model

6.4.1.1 Governing equations
In the width-averaged 2-D model, the open-channel flows with low sediment concen-
tration are governed by Eqs. (2.95)-(2.97), which can be written as follows when the
dispersion momentum transports are combined with the turbulent stresses and “ ∼ ”,