APPENDIX F 

 ESTIMATING THE WAVE CREST ELEVATION AT BREAKING ON A PLANE SLOPE 



The equations of Singamsetti and Wind (1980) can be used with the methods 

 developed in this report to predict the crest elevation at the breaking point 

 for monochromatic waves normally incident to a slope. This technique uses as 

 input water depth, d, wave height, H, and period, T, in a constant depth 

 region offshore of a plane slope, m. Deepwater wave height is found from 



h: = 



1.0 



tanh 



2TTd 



La 



Att d/L^ -| 

 sinh (Att d/L^)! 



where L^ is the v;avelength from Airy theory 



La = ^ tanh - 



Breaking wave height may be determined from 



(F-1) 



(F-2) 



H,. 



H' 0.575(m) 



(HI/LJ 



(F-3) 



where L^ is deepwater Airy wavelength 



?1 



L„ = 



277 



(F-4) 



Depth at breaking, d^, is found from 



db = lib (1-067) (m) 



-0. 1 55 



(HA/LJ 



0. 130 



(F-5) 



1 1 



for 40 ' "^ " 5 



-0.107 0.237 



d^ = H^ (1.761) (m) (H^/Lq) 



for m = 



The value of d^/L^ is used to determine A^ and Ao from Figure 6 in the 

 test of this report; A, is determined from the value of the beach slope 

 using Figure 7. Crest height at breaking, (ic^b' ^^ then given by 



Ai H, 



(nc)b = 



1.0 + tanh 



-A 2 l\ 



<-l) 



(F-6) 



73 



