Connecting 



Piston 



wave 



generator 



Load cell support 



2,500-lb load cell 



-2-m Wave Gage 



Rear anchor line support 



/ 



Top of tatvk 



32.0 40.0 



56.3 64.7 



Distance (m) 



89.0 100.0 



Note- Not drawn to 

 scale 



Figure 80. Experimental arrangement of the Goodyear Tire and Rubber Company 

 scrap-tire floating breakwater concept for prototype-scale trans- 

 mission and mooring tests conducted in CERC's large wave tank 

 (after Giles and Sorensen, 1978). 



The transmission coefficient, C t , versus the breakwater width-to- 

 wavelength ratio, W/L, is shown in Figure 81. This effectively constitutes 

 a design curve as all data are shown on this particular figure with the range 

 of incident wave heights indicated by the legend symbols. (Designers should 

 not extrapolate beyond W/L = 1.40, or apply these data to breakwaters with 

 a width of more than 12 modules.) Generally, the data show that as W/L 

 increases, the transmission coefficient, C t , decreases. Also, for the same 

 value of W/L, as the incident wave height increases, the transmission 

 coefficient decreases slightly. There is considerable scatter in the data 

 for W/L values less than 0.40 because the incident wave height was usually 

 small and was only 2 to 4 centimeters (0.05 to 0.13 foot) greater than the 

 transmitted height. Thus, a small change in the measured transmitted height 

 caused a large change in the value calculated for the transmission coeffi- 

 cient, C t . A comparison of the data at 2- and 4-meter water depths shows 

 that for the conditions tested the water depth does not appear to influence 

 the transmission coefficient. This observation is contrary to the expectation 

 that as more of the water depth is taken up by the breakwater section, the 

 wave attenuation should increase. 



b. Model-Scale Wave Attenuation Effectiveness . Harms and Bender (1978) 

 and Harms (1979a, 1979b) conducted scale-model tests of the Goodyear Tire and 

 Rubber Company scrap-tire floating breakwater concept. Waves were produced 

 by a hydraulically driven piston-type wave generator or by use of the wave 

 tank as a wind tunnel at windspeeds up to 64 kilometers (40 miles) per hour. 

 Wave heights were measured with capacitance wave probes, and mooring forces 

 were obtained from strain-gage cantilever-force transducers. The experimental 



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