Figure 24. Dlmensionless longshore current profiles as function of P-parameter 

 (from Longuet-Higgins, 1970, 1972). 



PX 



V2 iiv ^ 5 p^3/2 dV _ ^%^ ^ _^\ 



dx2 



DX 



(63) 



where again the right-hand side vanishes outside the surf zone and, 



NTTtang (g^) 



P = 





^f^ 



The dlmensionless parameter P now represents the relative importance of 

 lateral turbulent mixing of the wave orbital motion to the bottom frictional 

 resistance. Taking P = for no lateral mixing gives V = 1 at X = l(x = x, ) 

 and the triangular solution as before with V = outside the breakers. 



Longuet-Higgins (1970) solved equation (63) using the boundary conditions 

 that V-H) as X->0 and X-x» and internally that V and dV/dX are continuous at X = 

 1. He obtained the following results. 



87 



