Run 6

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.

Run 6

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.

Run 7

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.

Run 8

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

17

Chapter 4 Experiments and Results