Xp 



= 4.0£-° 



(64) 



which also can be written as 



Xp 



= 4.0nr 1/A 



(65) 



86. Plunge distance is also expressed as a function of the local surf 

 similarity parameter by 





(66) 



shown in Figure 18. Equation 66 was also obtained visually. 



87. Plunge distance normalized by deepwater wave height was compared 

 with £ (Figure 19) . The best visual fit equation is 



^ 



= 4.25£- c 



(67) 



88. Figures 17-19 all show scatter in the data, but plunge distance 

 normalized by H shows considerably more scatter. The high Xp/H — values 

 indicated on Figure 19 were all from the Galvin (1969) data set and from tests 

 in which he observed multiple wave forms, or solitons, present in the tank. 

 The subject of solitons will be discussed further in Part III. However, the 

 effect of solitons is not apparent if X^ is normalized by breaking wave 

 height. Therefore, based on the data set, plunge distance normalized by 

 breaking wave height should be used to determine plunge distance, and data are 

 least scattered if Xp/H b is plotted as a function of the offshore surf simi- 

 larity parameter. 



56 



