Sample calculation results are presented In Figure 42 where the hori- 

 zontal axis is the normalized mean water depth including setup. In Figure 

 42(a) for a narrow spectrum with mean wave steepness 0.02 and y = 0.8, the 

 effects of mean deepwater approach angle a are shown. Some optimum angle 

 (a - 60°) will produce a maximum current. For regular waves a = 45° gave 

 the maximum. This result is in direct contrast to the large-angle theory 

 for regular waves of Kraus and Sasaki (1979) (see Fig. 29). 



" 



^^60* 









as- 



/ / V' \\ 



H^/L^: QD2 









/// A- \ V\ 



s\ calcs I (narrow 



spectrum) 







// /v^* \ \ 



\ 







- 





\\ 









11/ /^^* \ \ 



^^%b 









[ 1 





1 





\ x- 



- D/H„ 



o.u - 



V . 



H,/L=0D05 



e. . IS* 



cilcsH: narrow spectrum, ^l\ variable 

 calc m: broad spectrum, h^/[^ = Q01 



WH, 



Figure 42. Calculated longshore current velocity profiles for (a) various 

 mean angles of incidence and (b) various wave steepness (from 

 Battjes, 1974a). a) 



143 



