shoreward bar angle on wave breaking, return flow measurements will be neces- 

 sary in future studies. The data points shown in the figures of this chapter 

 represent results from individual tests with different /3 3 — angles , unless 

 otherwise noted. 



124. A list of the base tests, including the control cases with no 

 bar, is given in Table 10. The first three digits of the case number specify 

 the deepwater wave steepness, shoreward bar angle, and seaward bar angle, 

 respectively. A fourth digit was used to differentiate tests that had iden- 

 tical wave and bar conditions. Results of the data analysis for the 

 monochromatic wave tests can be found in Tables Al and A2 . Table 11 

 summarizes the irregular wave tests. The letter "R" preceding the four-digit 

 case number in Table 11 indicates that irregular, or random, waves were 

 generated. 



Breaker Type 



125. Three breaker types were observed during the tests: spilling, 

 plunging, and collapsing. Breaker type transition values observed in the 

 experiment are shown as a function of offshore surf similarity parameter in 

 the upper portion of Figure 29. The offshore surf similarity parameter was 

 calculated by substituting tan/3 x for the slope m in Equation 4 (Battjes 

 1975) and using linear wave theory to calculate H and L from wave 

 heights and periods measured at the gage in the horizontal section of the 

 tank. Transition values between breaker types given by Battjes for plane 

 slopes are shown in the lower portion of Figure 29. Both plunging and 

 collapsing breakers in the present study for barred profiles occurred for 

 lower £ -values than predicted by the plane-slope values. Transition values 

 for barred profiles in this study were: 



surging or collapsing if £ > 1 . 2 



plunging if 0.4 < £ < 1.2 (75) 



spilling if £ < 0.4 



The lower transition values show that some waves that would break by spilling 

 on a plane slope will plunge if a bar is present, and some waves that would 

 plunge on a plane slope collapse on a barred profile. 



76 



