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Examples
94 MIKE 21 BW - © DHI
4.3 1DH Boussinesq Wave Module - Examples
4.3.1 Partial wave reflection
Purpose of the example
This fairly simple example is included to illustrate the process of wave propa-
gation and partial reflection of regular and irregular waves in a numerical
wave flume using the 1DH Boussinesq Wave Module. The enhanced Bouss-
inesq equations are solved in this example (as in practically all applications of
the 1DH Boussinesq Wave Module), i.e. the deep-water terms are included.
Model setup
The model setup is illustrated in Figure 4.62. The length of the flume is 390 m
with a uniform depth of 10 m.
Figure 4.62 Model setup (vertical cross-section). A 20 point wide sponge layer is
used at the left-hand side boundary and a 8 point wide porosity layer at
the other model extreme. The waves are generated internally at node j
= 21
The waves are generated inside the model domain, which is the most com-
mon method of forcing the 1DH Boussinesq Wave Module in practical appli-
cations. The two model boundaries (i.e. at j= 0 and j= jextr) are considered
closed. Opposite to applications of the 2DH Boussinesq Wave Module you do
not have to specify land points at the two model extremes.
Although a 20 point thick sponge layer is used in this example, you are in
general recommended to apply a sponge layer thickness corresponding to at
least once the wave length of the most energetic waves (corresponding to the
spectral peak wave period). In practice (with mesh size in the order of 1 m)
this means a 50-200 point thick sponge layer. In this example the thickness of
the 20 point wide sponge layer is 0.5-0.6 times the wave length correspond-
ing to the spectral peak wave period.
At the generation line (j= 21) a time series of fluxes and surface slope is
imposed. This time series is generated using the MIKE 21
Toolbox (wave
part) program Regular Wave Generation and Random Wave Generation . For