(3) The case of breakwaters with concrete armor units. The fric- 

 tion factor and porous media flow factors for concrete armor units are 

 unknown, but they are assumed to be similar to the properties of stone 



with an effective median diameter, d 



50^ 



of 



'50 



"50 



(17) 



Figure 35 shows observed and predicted transmission coefficients for 

 a breakwater with two layers of dolos armor units. There is excellent 

 prediction of transmission coefficients for long shallow-water waves 

 with the Madsen and White (1976) model overpredicting transmission 

 coefficients for waves with greater relative depth. This is the same 

 trend found in prediction of transmission coefficients for rubble- 

 mound breakwaters. 



B: 30cm-f* 

 hs:70cm 

 Ion 1.5 Slope 



® 

 Dolos Armor Units 

 I on 1.5 Slope 

 ® 



0.64<ds/h <0.86 

 0.0055 <d/gT2 < 0.055 

 0.0001 < H/gl^ < 0.0 I 2 

 B/h = 0.43, C = 0.46 

 a = 0.692, b = 0.504 



0.5 1.0 m 



u.o 





-r 





I 1 1 1 1 



d/gT^ Relative Depth 



1 y 



0.7 





• 

 X 





0.0065 Shallow 



0.016 Tronsifioncl / 



-^ 



0.6 



~ 



A 





0.055 Deep / 





^ 0.5 



o 



"S 0.4 

 a. 



- 







X /^ 



X ^ A 



X A 



- 



^ 0.3 



- 







x* / 



- 



0.2 



_ fl 



ax 



X 



X 



• 







0.1 

 n 



A 



/ 



V 



1 



/ 



1 1 1 1 1 



1 



0.1 



0.2 



0.3 0.4 0.5 

 Kjlobserved) 



0.6 0.7 



0.8 



Figure 35. Observed and predicted transmission coefficients 

 for a breakwater with dolos armor units (BW9) . 



47 



