height in a given depth since the figures take into consideration the 

 observed dependence of d^^/H^, and H^j/H^ on beach slope. The curves 

 in Figure 2-66 are given by 



_± ^ ^ (2-91) 



Hfc b-(aHj,/gT^) ' 



where a and b are functions of the beach slope m, and may be approxi- 

 mated by 



a = 1.36g(l-e-i5'") C2-92) 



b = 



1-56 (2-93) 



(l + e-19.5m) 



Breaking waves have been classified as spilling, plunging or surging 

 depending on the way in which they break (Patrick and Wiegel, 1955), and 

 (Wiegel, 1964). Spilling breakers break gradually and are characterized 

 by white water at the crest. (See Figure '2-67.) Plunging breakers curl 

 over at the crest with a plunging forward of the mass of water at the 

 crest. (See Figure 2-68.) Surging breakers build up as if to form a 

 plunging breaker but the base of the wave surges up the beach before the 

 crest can plunge forward. (See Figure 2-69.) Further subdivision of 

 breaker types has also been proposed. The term collapsing breaker is 

 sometimes used (Galvin, 1968) to describe breakers in the transition from 

 plunging to surging. (See Figure 2-70.) In actuality, the transition 

 from one breaker type to another is gradual without distinct dividing 

 lines; however, Patrick and Wiegel (1955) presented ranges of H^/L^ for 

 several beach slopes for which each type of breaker can be expected to 

 occur. This information is also presented in Figure 2-65 in the form of 

 three regions on the Uj^/^o vs. H^/L^ plane. An example illustrating the 

 estimation of breaker parameters follows. 



************** EXAMPLE PROBLEM 



***** 



GIVEN : A beach having a 1:20 slope; a wave with deepwater height of 

 H^ = 5 feet and a period of T = 10 seconds. Assume that a refraction 

 analysis gives a refraction coefficient, Kff = (bo/b)^/^ = 1.05 at the 

 point where breaking is expected to occur. 



FIND : The breaker height Hh and the depth db at which breaking occurs, 

 SOLUTION : The unrefracted deepwater height H^ can be found from 



h' / b \'''' 



— = Kp = T- (See Section 2.32), 



2-124 



