35 



- 





— r 



LEGEND 











SET- 



1,3,10, Smoll Scale 







t 



SPL- 



19,23,29,32,36, Prototype 



30 









i 



25 



- 







1 _ 







20 



- 







* 



i 



e 



A 



15 



- 









10 



- 







'i 



o 

 4 



5 



2 

 n 





-- 



L 



" • ^ * Zero-Domage Level 



OAfitfiflli ,. .1.,.,. ,.J 



1 2 3 4 5 



Dimensionless Wave Height(Ns) 



Figure 7. Small-scale and prototype damage trends 

 for d/gT^ = 0.0144. 



In addition to the information on damage trends. Figure 6 shows that the 

 small-scale tests exhibit less influence of wave period at the zero-damage level 

 than the prototype tests. The prototype Ng ' s have the characteristic parabolic 

 trend of wave period that was observed in the data for slopes of 1 on 2.5 and 

 1 on 5, as discussed by Ahrens and McCartney (1975), while the small-scale Nz's 

 show a more linear trend . 



2. Profile Shapes . 



Another way to evaluate scale effects, particularly at high damage levels, 

 is to compare the shapes of the damaged surface profiles for similar wave 

 conditions. This comparison requires the use of data where the dimensionless 

 damage is about the same at both small scale and prototype. Figure 8 shows a 

 profile comparison for tests with short period waves (d/gT^ = 0.0264) and gives 

 the dimensionless wave height and damage, respectively, for both tests in the 

 legend. The profiles were made comparable by increasing the small-scale test 

 dimensions by a factor of 10. The shapes of the two profiles were similar, and 

 the causative dimensionless wave heights were about the same. Figure 9 is 

 similar to Figure 8 except the profile comparison was for tests with long 

 period waves (d/gT^ = 0.0037), and the causative dimensionless wave height was 

 approximately 18 percent smaller in the small-scale tests. 



19 



