TABLE 1 



Characteristics 



Measurement of 





Gor/puted 



Slopes 





of 



Slopes 





Slopes 



Deduced 



Waves 



(i - Tga), 





Irribsrren 



from For- 











Forraala 



mula 1 



2h (cm.) 



2T (sec.) 



Total 

 break- 

 ing 



Total 

 Refle- 

 ction 



Av- 

 er- 

 age 



" = ^xE^T 



i = Tga 



1 



2 



3 



h 



5 



6 



7 



5,5 



0„66 



0.1i2 



0.86 



Oo6k 



0.66 



0.80 



hS 



0.92 



0.29 



0,59 



o,hh 



0.1i2 



0,50 



h.S 



1.00 



0,33 



0,li9 



oM 



0,38 



O0I1.6 



The reflecting power (R) of the maritime vrorks is defined as the 

 ratio beti-reen the airplitudes of the reflected and incident swells or 

 2h,/2h| R = h,/h. F^om equation 1 the author deduces that theoretically 

 the reflecting power (R') would have the following value: 



R' - 



J max (from equation l) 

 "y (actual) 



where R' < 1 



(2) 



Then also the portion of the reflected wave energy is reduced due to the 

 turbulence produced in the orbital movement at contact xfith the active part 

 of the slope (that portion of the slope betiijeen one wave height 2h above the 

 mean water level and one wave height below). A coefficient p for "intrinsic" 

 reflection of the structure is introduced in equation 2 such that: 



R = kj^/h = pR' 



(3) 



Figure 2 shows graphically the theoretical reflecting power (R') plotted 

 against the parameters of slope and deep water steepness ratio of the incident 

 wave. I-iultiplication of the ordinate (R') by the coefficient p yields the 

 reflecting power (R) of the slope for a Xirave of particular steepness. 



Tlie author applies data from experimental tests made at the Laboratory 

 of Delft by Schoemaker and Thijsse to verify his theory outlined above. 

 Goirparison of experimental measurement and application of equations 2 and 3 

 are shown in Figures 3 and li for smooth structujres with continuous slopes 

 and in Figure 5 for discontinuous slopes. It is noted that values of the 

 "intrinsic" coefficient of reflection p of 0.8 and 0.7 respectively were 

 used for tliis comparison. For the case of the discontinuous slopes with 

 the vertical face at the toe (tests b) the reflected xirave appears reduced 



