Geoscience Reference
In-Depth Information
Domain decomposition and model
integration
Many problems in river engineering exhibit geometric irregularities andmultiple length
and time scales in flow velocity andmass concentration. To handle these characteristics
effectively, the computational domain is often decomposed into subdomains that may
be represented by meshes with different grid densities and topologies, and treated
by models with different dimensions and complexities. The multiblock algorithm,
coupling of 1-D, 2-D and 3-D models, and integration of channel and watershed
models are introduced in this chapter.
8.1 MULTIBLOCK METHOD
8.1.1 General considerations
The multiblock method divides the entire computational domain into blocks, as shown
in Fig. 8.1, and generates the mesh for each individual block independently. The gov-
erning equations are first solved in each block with information exchanged at block
boundaries, and the results in all blocks are then assembled to obtain the global solu-
tion. The multiblock method allows much greater grid flexibility and local refinement
than the single-block method does.
To facilitate the exchange of information, an interface between two adjacent blocks
needs to be constructed. The grids on the blocks can be patched or overlapped around
the interface, as shown in Fig. 8.2, depending on the numerical methods used. On the
Figure 8.1 Sketch of domain decomposition.
 
 
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