Reference Manual
138 MIKE 21 BW - © DHI
Final breaking angle
During the transition from the initial breaking to a bore-like stage in the
inner surf zone, the critical angle is assumed to change gradually from
the initial breaking angle to a smaller terminal angle, the final breaking
angle. The default value is 10 degrees.
Half-time for cut-off roller
This time defines the transition between the two breaker. The default
value is Tp/5, where Tp is the wave period of the most energetic wave
components.
Wave direction
This direction is the main or characteristic wave propagation direction
of the breaking waves relative to true North. The default direction is
270ºN corresponding to waves from West.
Type of breakers
Depth-induced wave breaking of individual waves starts when the wave
height becomes greater than a certain fraction of the water depth. As a rule of
thumb, the wave height of an individual wave at breaking is often said to be
around 80% of the water depth, but this is a very approximative number.
Breaking waves are generally divided into three main types, depending on
the steepness of the waves and the slope of the shoreface:
Figure 5.24 Spilling
Spilling takes place when steep waves propagate over a flat shoreface. Spill-
ing breaking is a gradual breaking process which takes place as a foam bore
on the front topside of the wave over a distance of 6-7 wave lengths.
Figure 5.25 Plunging
To Next Page
Loading...