^ = 0.3 



-1/3 



H„ ~ 



I Lo J 



(15) 



The relationships of McCowan (1891) and Munk (1949) have been widely accepted 

 in the past because of the hypothesis that periodic waves near the break point 

 behave as solitary waves. The following paragraphs present selected relation- 

 ships developed for breaker indices using periodic waves. 



26. The first major laboratory experiment on breaking waves was con- 

 ducted by Iversen (1952). Iversen generated periodic waves of steepness in 

 the range of 0.0025 < H /L < 0.0901 on four different uniform beach slopes 

 (1/10, 1/20, 1/30, and 1/50) and developed curves for the breaker height index 

 versus deepwater wave steepness. The curves show fij, decreasing with in- 

 creasing H /L . Iversen also noted breaker height was higher for the 

 steeper slopes. This experiment provided breaker data over a broad range of 

 slopes and wave steepnesses, and the data set is often referenced in breaking 

 wave studies. 



27. Ippen and Kulin (1955) conducted experiments with solitary and 

 oscillatory waves and concluded that oscillatory waves do not behave as 

 solitary waves near the break point because of backwash from preceding waves. 

 They also noted 7 b increased as wave period increased, which implies the 

 breaker depth index increases as H /L decreases, since L is directly 

 related to wave period. 



28. Galvin (1969) performed laboratory experiments with periodic waves 

 on three different uniform slopes (1/5, 1/10, 1/20) and found that if his data 

 were combined with the Iversen (1952) data, 



1 



= 0.92 m > 0.07 (16) 



7b 



1 



1.40 - 6.85m m < 0.07 (17) 



7b 



29. Collins and Weir (1969) derived the following expression from 

 linear theory and experimental data of Suquet (1950), Iversen (1952), and 

 Hamada (1963): 



21 



