K^ = 



1.0 



t C l s 



<i? n 



■:jiWc' ' 



3\H / "4\ ,2 _ 

 mo/ \d 5Q L p/ 



(13) 



for 



mo 



where 



C = 1.188 



C = 0.261 



C = 0.529 



C. = 0.00551 

 4 



Equation 13 explains about 92 percent of the variance in K for the 167 



tests where F/H < 1.0 . Equation 13 is the result of a considerable amount 

 mo 



of trial and error effort to find an equation which fits the data well, makes 

 physical sense based on current understanding of the phenomenon, approaches 

 the correct limiting values, and is reasonably simple. The regression analy- 

 sis for Equation 13 is shown in Appendix B. 



34. If Equations 12 and 13 are used, the transmission coefficient can 

 be predicted over the entire range of conditions tested in this study. Pre- 

 dicted values of K were made using Equation 12 for F/H > 1.0 and Equa- 



t mo 



tion 13 for F/H < 1.0 . This prediction method will be referred to as the 

 mo 



wave transmission model. Figures 19, 20, 21, 22, and 23 show predicted and 



observed values of K as a function of F/H for subsets 1 and 2, 3 and 4, 

 t mo 



5 and 6, 7 and 8, and 9 and 10, respectively. Figures 19 through 23 indicate 

 that the wave transmission model does a good job of predicting individual test 

 results and produces trends very similar to those of the observed data. 



35. In addition to investigating the attenuation of wave energy passing 

 over and through the reef, it is also possible to determine the relative shift 

 in wave energy caused by the structure. The shift in wave energy is measured 

 by the ratio of the period of peak energy density of the transmitted wave to 

 the period of peak energy density of the incident wave. Figure 24 shows the 

 shift in peak period as a function of relative freeboard. What is surprising 



32 



