breakwaters are larger and permeable, have flatter crests, and are not always 

 submerged. However, the reef reflection parameter relates area and height of 

 the structure to reflection and was considered appropriate to examine for 

 describing reflection in the present study. 



Breaker Index 



22 . A schematic of a wave at incipient breaking is illustrated in Fig- 

 ure 4. Breaking is shown to take place over an idealized bar, where h b is 



SCALE 



SCALE 



CENTIMETERS 



Figure 4. Definition sketch of wave at 

 incipient breaking 



the water depth at breaking, /?! is the seaward bar angle, and /? 3 is the 

 shoreward bar angle. The break point can be defined in several ways. 

 Singamsetti and Wind (1980) listed possible definitions as: 



a. The point where the wave cannot further adapt to the changing 

 bottom configuration and starts to disintegrate. 



b. The point where the horizontal component of the water particle 

 velocity at the crest becomes greater than the wave celerity. 



c. The point where the wave height is maximum. 



d. The point where part of the wave front becomes vertical. 



e. The point where the radiation stresses start to decrease. 



f . The point where the water particle acceleration at the crest 

 tends to separate the particles from the water surface. 



g. The point where the pressure at the free surface given by the 

 Bernoulli equation is incompatible with the atmospheric 

 pressure. 



19 



