Irregular Wave Tests 



184. Maximum breaker height from irregular wave tests was compared with 

 the predictive expression of Goda (1975) using A - 0.18 . Maximum wave 

 height was predicted well for p 1 < 10 deg . Significant wave height was also 

 compared with the Goda expression with A = 0.12 , which also gave good 

 results for fi x < 10 deg . The minimum coefficient specified by Goda 



(A = 0.12) was reduced by Jl to predict values for rms wave height based on a 

 Rayleigh distribution, which gave A - 0.09 . The equation reasonably pre- 

 dicted wave heights for /9 X < 10 deg and overpredicted wave heights for 

 P x = 15 deg . 



185. Wave height-to-water depth ratio was plotted as a function of hor- 

 izontal distance from the shoreline for irregular waves. The ratio was not 

 constant through the inner surf zone, but increased uniformly into shallow 

 water for plane-sloping beaches and was double peaked for single barred 

 profiles. 



186. Irregular wave runup was normalized by (H s ) , plotted as a func- 

 tion of the surf similarity parameter, and compared with the expression of 

 Ahrens (1981). The Ahrens expression predicted runup for the plane-slope 

 tests well, but overpredicted runup with bars in the tank. The predicted 

 values of Ahrens showed good agreement with the measured values if the fore- 

 shore beach slope (1/30) was used to compute the surf similarity parameter 

 rather than seaward bar angle . Runup thus appears to depend mainly on the 

 foreshore slope and not on the presence of a bar. 



Recommendations for Future Study 



187. This study verified the strategy of using solid but adjustable 

 bars for examining wave breaking on realistic nearshore bottom shapes. It is 

 recommended to continue the line of study to more exact replication of bar 

 forms and sizes, although gently sloping bars will require considerable 

 resources, equipment, and effort to build and emplace. 



188. It was clearly demonstrated that bars alter the characteristics of 

 breaking waves. This is due to the steeper seaward bar slope, volume of water 

 shoreward of the bar, and the speed of the return flow. In future 



147 



