MIKE 21 BW, User Manual, Page: 139 / 196

Calibration Parameters
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Plunging is the form of breaking where the upper part of the wave breaks
over its own lower part in one big splash whereby most of the energy is lost.
This form of breaking takes place in case of moderately steep waves on a
moderately sloping shoreface.
Figure 5.26 Surging
Surging is when the lower part of the wave surges up on the shoreface in
which case there is hardly any surf zone. This form of breaking takes place
when relatively long waves (e.g. swell) meet steep shorefaces.
White-capping or top-breaking is steepness-induced wave breaking which
occurs on deeper water when the wave height becomes to large compared to
the wave length. White-caps can be observed in the figure below.
Figure 5.27 White caps in open water
5.3.9 Moving shoreline
The incorporation of a moving shoreline in MIKE 21 BW is based on the fol-
lowing approach: the computation domain is extended artificially by replacing
the solid beach by a permeable beach characterised by a very small porosity.
Near the moving shoreline the water surface will insect with the sea bed and
continue into the porous beach. Hence the instantaneous position of the
shoreline is simply determined by this intersection. Please read pp. 263-266
in Madsen et al (1997a) included in the scientific documentation.