CENTIMETERS 



Figure 35. Collapsing wave at incipient breaking 



on the front face of the wave crest; i.e., breaking begins before the incident 

 wave has reached the depth- limited break condition. The wave crest was 

 located in deeper water at incipient breaking for these conditions, which 

 increased h b and lowered values of 7 b . The wide scatter of data indicates 

 the strength of the return flow is a major factor influencing breaker depth at 

 higher £ — values . 



136. A breaker depth analysis was made for increasing values and 

 decreasing values of 7 b in Figure 34, excluding the wide scatter data in the 

 transition region (0.9 < £ < 1.6) . A linear regression was performed on the 

 increasing values of 7 b for spilling and plunging waves occurring over bars 

 in which f) 1 < 10 deg, which is approximately the maximum seaward bar angle 

 observed in nature. A relationship for collapsing waves with £ > 1.6 was 

 made by a best- fit line drawn through 7 b -values . The resulting relation- 

 ships for breaker depth index was: 



7 b = 0.41 + 0.98£ o for 0.3 < £ < 0.90 

 7b = 1.45 - 0.22£ o for 1.6 < £ < 3.5 



(78) 



The coefficient of determination for the regression analysis was 0.85. Equa- 

 tion 78 is shown in Figure 36a and b and also in Figure 34. The decreasing 



87 



