0.04 





0.03 -# 



0.02 



0.01 - 





Eqn 3.3-16 



• T= l.0s-| I 

 in 



■ 1.5s J 10 

 o Bowen et al.(l in 12)- 

 D Smith (I in 10) 

 A Smith (I in II) 

 _j I 



1.0 



I.I 



.2 



1.3 



1.4 



1.5 



/b 



Figure 49. Wave setup versus breaker ratio, y^^: Theory from equation (8) 

 versus experiments on slopes around tan 3 = 0.1 (after Gourlay, 

 1978). 



A large difference in observed and calculated wave setup was also reported. 

 It was concluded that the linear wave theory only roughly followed the trend 

 of the observed results. 



Finally, Stive (1980) briefly discusses preliminary results of the 

 first known direct laboratory measurements of internal velocity and pressure 

 fields to directly calculate momentum and energy flux in breaking waves. 

 All previous experimental studies of the surf zone were literally on the 

 surface, i.e., wave gage surface variations or MWL readings. The use of a 

 two-component laser-Doppler velocity system, minature pressure transducers, 

 and electronic data recording and analysis systems greatly facilitated the 

 work. A sample from one experiment is summarized in Figure 50. The radia- 

 tion stress for a number of surf zone locations was directly calculated from 

 equation (1), and the values used in equation (28) are close but slightly 

 above the measured n values. Use of linear wave theory and Hj-j^g measured 

 gave excessive wave setdown and setup. It will be extremely helpful to 

 study the published results of these experiments. 



In summary, it can be concluded that wave setup for normal wave inci- 

 dence of regular waves on plane beaches as given by equation (35) is 



161 



