Wa = weight of individual armor or stone
= specific weight of an individual armor unit or stone
a
lm/lp = linear scale of the model
Sa = specific gravity of an individual armor unit or stone relative to the
water in which it is placed; / w, in which w is specific weight of
water
Material sizes and densities for prototype and model armor layer W1, under-
layer W2, and core W3 are listed in Table 2.
Table 2
Prototype and Model Material Sizes
Prototype
Model
Material
Sa
Wa
Sa
Wa
2.62
11 tonnes
2.29
145.2 g
W1
2.62
8 tonnes
2.28
104.3 g
W1
2.9 - 3.1
750 - 1800 kg
2.65
9.2 - 22.1 g
W2
2.9 - 3.1
12.5 - 250 kg
2.65
0.15 - 3.1 g
W3
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 1V 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
7
Chapter 2 The Model
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