Experiments and Results
This chapter first describes the experiments and the results achieved. The
data are then compared with other laboratory and field data.
Description of Experiments
The initial sequence was a short series of runs to determine appropriate condi-
tions for subsequent experiments. Table 2 summarizes the various runs and re-
sults. Typically a run was conducted without waves until equilibrium was reached
for tidal conditions only, then waves were generated. The wave direction was
perpendicular to the shoreline. Wave height at the generator (0.3-m water depth)
was 3 cm with a 1-sec period. The waves were monochromatic. There was no
sediment input from adjacent shorelines, so that only that sediment located on the
inner shoulders and within the inlet entrance was available for transport in the
inlet system. The initial experiments were performed with the fine sand
(0.13 mm), and later experiments used the 0.26-mm sand. Two tidal periods,
1.76 hr (based on a Froudian scale of 1:50) and one-fourth that amount, or
0.44 hr, were run for each sand type. Measurements of channel area were made
relative to mean tide level. The tide ranged 1.52 cm from 0.0 mean tide level.
Water temperatures were in the range of 23 to 26 C except for Run 9, where the
Appendix A provides detailed experiment information. Included are plots of
minimum area, maximum velocity, maximum head difference, and bay tidal range
over the test duration, typically recorded for each tidal cycle. Also included are
inlet cross sections measured during and at the conclusion of the experiment.
Discussion focusses primarily on Runs 4, 5, 8 and 9, which are complete experi-
mental sets, run until an equilibrium area was obtained. Time series data for these
runs are presented in Appendix B.
This run was part of a series of preliminary experiments to determine appro-
priate initial operating conditions. Runs 1 to 3 involved the initial model ar-
rangement while alterations were being made in channel depth and length, and so
they were a continuum of trial experiments. An initial 4.4-m-long channel with
Chapter 4 Experiments and Results