4 Physical Model Results
The purpose of these laboratory experiments was to measure wave height and
wave direction in the lee of coastal structures and inside an inlet entrance to
verify numerical techniques and models for combined wave diffraction,
refraction, and shoaling. This chapter presents the results of the wave height and
direction measurements collected for the four structures. Wave height data were
plotted spatially and contoured. Spectral energy density versus frequency plots
are also examined. Wave direction measurement techniques and results are
discussed in Chapter 5.
Structure 1
The Structure 1 configuration represented a semi-infinite offshore breakwater
with a shoreward sloping bottom behind the breakwater (Figure 5) terminating at
the beach. Appendix B contains data tables for the gauge arrangement for each
experiment. A total of six experimental conditions were studied as noted in
Table 2. For an incident wave direction of 0.0 deg, irregular waves of 0.8 sec,
6.1 cm (0.2 ft), and 1.6 sec, 4.6 cm (0.15 ft) and monochromatic waves of
0.8 sec, 4.6 cm (0.15 ft) were produced. The wave generator was repositioned
for a 20-deg incident wave direction and the same three wave conditions
repeated. Initial experiments with the 0-deg wave approach indicated very small
wave heights at the distant wave gauges behind the breakwater, so to obtain
additional wave energy penetration behind the breakwater, the 20-deg
experiments were performed.
The tables in Appendix B contain gauge number, depth at the gauge, average
water surface elevation relative to the still-water level, significant wave period,
significant wave height, average wave height, and maximum wave height. The
data are arranged in tables for each gauge arrangement, as shown in Figure 5.
Appendix C presents contoured dimensional wave height plots. Figure 15 shows
the 0.8-sec experiment wave height contours, with mean wave direction given at
selected locations as determined from the velocity gauges. The x-y arrows
depicted on the plots indicate the basin x-y position that corresponds to the plot
origin (0,0). Appendix J contains sample spectral energy density versus
frequency plots for selected wave gauge locations. The overall basin bathymetry,
the shore-parallel breakwater structure, the dogleg jetty structure, and the parallel
jetties structure are referenced in Appendix K. The large volume of data has
been placed on the accompanying CD. The location of the wave gauges and
breakwater within the coordinate system is given in Appendix L.
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Chapter 4 Physical Model Results
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