W a = weight of individual armor or stone 



y a = specific weight of an individual armor unit or stone 



ljl p = linear scale of the model 



S a = specific gravity of an individual armor unit or stone relative to the 

 water in which it is placed; yjy w , in which y w is specific weight of 

 water 



Material sizes and densities for prototype and model armor layer W„ under- 

 layer W 2 , and core W 3 are listed in Table 2. 



Table 2 



Prototype and Model Material Sizes 



Material 



Prototype 



Model 



S„ 



w„ 



S a 



w a 



W, 



2.62 



1 1 tonnes 



2.29 



145.2 g 



w, 



2.62 



8 tonnes 



2.28 



104.3g 



w 2 



2.9 - 3.1 



750 -1800 kg 



2.65 



9.2 - 22.1 g 



w, 



2.9-3.1 



12.5 -250 kg 



2.65 



0.15-3.1 g 



Experiment Facilities and Equipment 



Experiments were conducted in a 29.3-m-long, 29.6-m-wide, 1.5-m-deep 

 wave basin. The model was constructed and molded of concrete to represent 

 approximately 825 m of shoreline encompassing the harbor and breakwater 

 location. Contours were molded to -20 m CD, and a IV on 5H transition slope 

 was molded from the -20-m contour to the model floor elevation of -21.3 m CD. 

 Wave absorber was placed around the perimeter of the basin to minimize the 

 effects of reflection. A photograph of the model is shown in Figure 5. 



Waves were generated by a piston-type electronically controlled hydraulic 

 system. Displacement of the wave board was controlled by a command signal 

 transmitted to the board by a DEC Micro VAX II computer, and waves were 

 produced by the periodic displacement of the board. Irregular wave command 

 signals to drive the board were generated to simulate a Texel, Marsen, and 

 Arsloe (TMA) shallow-water spectrum (Hughes 1984) for the design wave 

 periods. 



Water surface elevations were recorded by single wire capacitance-type 

 gauges, sampled at 20 Hz. Eight gauges were used for calibration and testing. 

 Three gauges (Gauges 1 through 3) were positioned on the flat portion of the 

 model floor (-21.3 m CD) 3 m from the generator in an array that allowed 



Chapter 2 The Model 



