126. Breaker type was also subjectively classified as "well-behaved" or 

 "confused." The well-behaved breakers were waves that broke by depth-limited 

 conditions (spilling and plunging breakers) , and the confused breakers were 

 believed to be waves that broke as a result of strong return flow (collapsing 

 breakers) . A relative length parameter was introduced to quantify well- 

 behaved and confused breakers. The relative length parameter was defined as 

 the ratio of the length of the seaward bar face s 1 , i.e., the horizontal 

 distance from the bar crest to the seaward toe of the bar, to the wavelength 

 at breaking L^ . The wavelength at breaking was calculated by linear 

 shallow-water wave theory as 



1^ = T(gh b ) 1 / 2 



(76) 



Figure 30 shows well-behaved and confused breakers as a function of the rela- 

 tive length parameter. Well-behaved breaking occurred for s 1 /h b > 0.75, 

 which means well-behaved or depth- limited breaking occurs if s x is at least 

 75 percent as long as the wavelength at breaking. If s 1 < 0.751^ , the bar 

 probably had little effect on wave deformation leading up to breaking and, 

 instead of gradually shoaling, waves broke by tripping over the bar. 



127. Under natural conditions on a sandy beach, the bar and incident 



Breaker Type 

 □ Weil-Behaved 

 * Confused 



nn □ ann cud en 



s1/Lb 



Figure 30. Breaker type as a function of the 

 relative length parameter 



81 



