a. Hour 1
b. Hour 20
Hours 1 and 20 of Run 5. Hour 1 was at initiation of run, hour 20 at
conclusion of tidal currents portion of run (no waves up to this point)
phasing of the tidal currents with respect to tidal elevation. The reduction in
channel length reduced time to equilibrium significantly.
This run was a demonstration, and only a limited amount of data was col-
lected. Conditions were similar to the previous experiment, and only four tide
cycles were run.
This was the first experiment with the larger grain size sand (0.26 mm) as the
movable bed. A power failure limited the experiment to six tidal cycles and
washed out the inlet when the pumping system was cut off.
This was the first complete experiment with the 0.26-mm-diameter sand and
the 105-min tide period. It took eight cycles of the tide-only condition to reach an
equilibrium area of 0.0813 sq m (0.875 sq ft). Maximum currents at equilibrium
were 0.25 m/sec (0.82 ft/sec) with a tidal prism of 55.19 cu m (1,949 cu ft). The
wave generator was then run with the standard wave for eight cycles until a new
equilibrium was reached. The minimum area increased slightly to 0.0875 sq m
(0.942 sq ft), currents to 0.27 m/sec (0.90 ft/sec) and tidal prism to 57.39 cu m
(2,027 cu ft). Figure 10 shows the inlet at the tidal current equilibrium and tidal
current plus waves equilibrium. The channel sides remained straight and parallel
for the tidal current equilibrium; however, following the waves and current
Chapter 4 Experiments and Results