1.20 



.00 __« 



0.80 - 



0.60 



5 0.40- 



0.20 - 





I 



1 







1 







1 

 NOTE: 



1 1 1 



Data collected for the following test 

 conditions: 





- 



— — 01 



* 



• 

 X 



X« 4 1 * X 1 



J 



• 



s 



+ 



X 



I 



■ 



1 



k 

 ■ 



k 



2- and 4-meter water depths 

 0.2- to 1.4-meter wave heights 



9.5- to 49.6-meter wavelengths 



8.6- and 12.8-meter breakwater widths 



- 







LEGEND 















\ 





- 



Height (cm ) 

 o lo 29 















\ 1 ■ v 

 7 '\ 



- 





• 



30 to 39 



















i 



40 to 49 















*\ 







+ 



50 to 59 



















X 



60 to 69 















\ 







o 



70 to 79 



















V 



80 to 89 





















* 



90 to 99 





















■ 

 1 



100 to 119 

 120 to 140 



I 







1 







1 



i i i 





0.20 



0.40 0.60 0.80 1.00 1.20 



Ratio of Breakwater Width-to-Wavelength W/L 



.40 



.60 



Figure 81. Design curve for determining width, W, of the Goodyear Tire and 

 Rubber Company scrap-tire floating breakwater concept for various 

 wavelengths, L, and allowable transmission coefficients, C t 

 (after Giles and Sorensen, 1978). 



arrangement for these scale-model tests is shown in Figure 82; the definitive 

 sketch in Figure 83 describes the pertinent variables investigated in that 

 study. 



The use of regular waves had been intended for all these laboratory tests, 

 but it was impossible to generate regular waves less than 1.3 meters (4 feet) 

 long at the test section location. Since shorter waves with periods of 1 sec- 

 ond or less were required to adequately define the wave attenuation perform- 

 ance of the model breakwater and irregular waves had to be used at the test 

 section, it was necessary to combine the irregular wave (narrow-spectra) data 

 with that from other tests with regular waves. The equivalent monochromatic 

 wave height and wavelength needed for this purpose were defined as the average 

 wave height and peak-energy wavelength, respectively, obtained from time- 

 series analysis of the water surface elevation. The number with each data 

 symbol represents the wave steepness in percent, and the letters r, m, and 

 w designate regular waves, machine-generated wave spectra, and wind-generated 

 waves, respectively. The letter x indicates that the value of the transmis- 

 sion coefficient, C t , was obtained directly from the analog trace and not 

 from time-series analysis. The relationship between the transmission coeffi- 

 cient, C t , and the relative breakwater width, L/W, is presented in Figure 

 84 for these model-scale data of Harms and Bender (1978). 



129 



