_I00 zoo 300 400 500 600 700 80 



M&Kimum set- up 



3roikwa.-tar Incident v\ 



(a.) M«&n water laval con-tours 



V - m 



100 200 300 400 JOO 600 700 800 





 100 



Minimum 6et-up 





\ -0.0S \ 



- -0.01 V. \^^ 

 > i» in m^s 



\^ "^^.^^X^ y/ 3rexk point 



? 



200 



^-^^^^ ^„^^ y y 



/ 





- _^-.'^ y' 





300 









\ 





400 





Breikwatcr 



Incident wo-ve crc&t 





(b) Stres.mlin«a 



£Ul (, tan^) = O.oa T =. 10 s Hg . I m V =. 0.3 



dx 



Figure 34. Solution for an offshore breakwater (from Liu and Mei, 1975), 



The model was improved in 1979 by including the convective accelerations 

 and lateral mixing stress terms (Ebersole and Dalr3miple, 1979, 1980). In 

 addition, the full, strong current large-incidence angle bed-stress model 

 (Liu and Dalrymple, 1978) was employed. Eddy viscosity was calculated by 

 equation (55) and from Longuet-Higgins (1970) for the shore-normal direction. 

 In the alongshore direction, a constant coefficient v was employed. 



Numerical integration was by the finite-difference method. The explicit 

 three level leapfrog-type scheme employed required a special starting routine 

 to generate the initial conditions at two time levels. In addition, special 



126 



