2
Experiment Arrangement
This chapter describes the design of the idealized physical model inlet, ar-
rangement of equipment, and measurement procedures.
Idealized Inlet Facility
An idealized inlet was designed to fit in a 46-m- (150-ft-) wide by 99-m-
(325-ft-) long concrete basin with a 0.6-m- (2-ft-) high wall that is part of the Ide-
alized Inlet facility (Seabergh 1999) of the Coastal Inlets Research Program
(CIRP). The approach was to design an inlet with simplified bathymetry and
fairly steep beach slopes so that additional features (such as an ebb shoal) could
easily be added. Also, it was anticipated that a fine sand would serve as both a
tracer and as a fully mobile bed that could be placed over the concrete bottom in a
thick layer. A 1:50 undistorted scale was assumed to determine reasonable inlet
dimensions to model; however, other scales can easily be assumed to accommo-
date the study of specific processes because of the simplified bathymetry.
Figure 1 shows the basin area. The ocean-side parallel contours were deter-
mined by following an equilibrium profile equation from Dean (1977):
h = Ax 2 3
(5)
where
h = still-water depth
A = coefficient determined by sediment characteristics
x = distance seaward from the shoreline
A value of A = 0.24, m1/3, was used as it represented a relatively steep beach. The
contoured ocean beach slope extends to the 18.3-cm (0.6-ft) mean low water
(mlw) depth (or 9.1-m (30-ft) depth if scaled by 1:50) and is linearly transitioned
to the basin floor at a depth of 30.4 cm (1.0 ft) (or 15.2 cm (50-ft) depth if scaled
by 1:50). The inlet throat region converges to a depth of 15.2 cm (or if scaled to
1:50, 7.6 m (25 ft)) relative to an mlw datum. The minimum width is 244 cm
across the inlet between mlw contours (or if scaled by 1:50, it represents a width
of 122 m (400 ft)). Figure 2 shows the inlet throat and entrance channel with
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Chapter 2 Experiment Arrangement
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