Figure 7. Notation for diffraction study. 
In the case where the long groin is in the previously defined wave diffrac- 
tion zone as in Figure 6, it is assumed that the wave energy which reaches the 
groin is absorbed by friction. It is also assumed that the combined effects of 
diffraction and refraction of a wave spectrum can simply be represented by a 
sinusoidal variation of wave height along the breaking line (Mobarek and Wiegel, 
1966) (Fig. 7). 
Assuming that Kp(x) is of the form sin k(x - X5) as shown in Figure 7, 
Such as Kp at A= 0, Kp at C = 1, then to satisfy these conditions 
T 1 1 
oe oe (ean CS Ss) En Gers a) (29) 
which after some simple trigonometric transformations can still be written 
k = 7 cos 2a (30) 
mats O 
to satisfy the equation expressing the conservation of energy flux, such as 
given by equation (29), then 
and Kp(x) = H(x)/H, is given by 
os (2 1/2 2 
Kp (x) = (2 een) sin (ee ee bso & can CS> = 2031) (31) 
sin Ot Ay 
2 | 
