c. Det ermination of the Transmission and Reflection Coefficient 

 of Trapezoidal, Multilayered Breakwater s. From the results 

 obtained in Sections IV. 3. a and iy.3.b it is now possible to estimate 

 the transmission and reflection coefficient of the trapezoidal, 

 multilayered breakwater (Fig. 25) since the external as well as the 

 internal energy dissipation has been accounted for. From the description 

 of the procedure given in Section IV. 1 it follows that the transmitted 

 and reflected wave amplitudes, | a^ | and |a^l, are given by 



l\l = Vi = Vii^i ^'''^ 



and 



R^a^ = R^R^.a. . [174) 



II I II 1 



The transmission coefficient, T, and reflection coefficient, R, are 

 therefore obtained from the results listed in Tables 6, 7, and 8 since 



T = — ^ = T,R,, (175) 



a. Ill 



1 



and 



1 

 The resulting estimates are shown in Table 9. 



4. Comparison Between Predicted and Observed Transmission and 



Reflection Coefficients of a Trapezoidal, Multilayered Breakwater . 



The preceding section has illustrated the use of the approximate 

 method for the determination of transmission and reflection coefficients 

 of trapezoidal, multilayered breakwaters described in Section IV. 1. 

 The breakwater characteristics as well as the characteristics of the 

 incident waves used in Section IV. 3 were chosen to correspond to the 

 experiments performed by Sollitt and Cross (1972), and the predictions 

 given in Table 9 may therefore be compared directly with the 

 experimentally observed values of the transmission and reflection 

 coefficients given by Sollitt and Cross (1972, App. G) . This comparison 

 between predicted and observed transmission and reflection coefficients 

 is shown in Figure 26, where the values of T and R are plotted against 

 the incident wave steepness, H./L. 



From the comparison presented in Figure 26 the predicted reflection 

 coefficients are in excellent agreement with the observed reflection 

 coefficients for lower values of the incident wave steepness. For larger 

 values of the incident wave steepness the predicted reflection 



96 



