MIKE 21 BW - Page 37

2DH Boussinesq Wave Module - Examples
37
Figure 4.11 Model setup for Hanstholm harbour. Upper panel shows the bathyme-
try, the lower left panel the absorbing sponge layers (20 point wide) and
the lower right panel the areas where partial wave reflection is required
(3-5 points wide)
In this example we consider a case having H
m0
= 1.0 m and T
p
= 8 s. The
waves are coming from N and the minimum period of interest is set to T
min
= 5
s. As the maximum water depth in the model area is h
max
= 17.5m it is neces-
sary to include the deep-water terms (h
max
/L
o
= 0.45). The minimum depth is
h
min
= 4 m. The incoming waves are synthesised based on a mean JON-
SWAP spectrum.
For visualisation purposes oblique incident unidirectional irregular waves are
used (you can modify the specification, if you like, in order to see what hap-
pens if e.g. directional waves are applied). The input data files are generated
using the Random Wave Generation tool in the MIKE 21 Toolbox (open the
file Hanstholm_Harbour_Preprocessing_Data.21T by double clicking).
To reduce the computational time artificial land is introduced outside the main
breakwaters of the entrance leaving only a smaller area outside the harbour
from where the waves can enter the harbour.
A grid spacing of 5 m is chosen and a time step of 0.2 s. This results in about
6 grid points per minimum wave length, 25 time steps per minimum period
and a maximum Courant number of 0.52 in the deepest part of the model
area. Please note that the space- and time-resolution in this example is less