2
Overview of the Laboratory
Facility
General Layout
The Large-scale Sediment Transport Facility (LSTF) has dimensions of 30 m
cross-shore by 50 m longshore by 1.4 m deep, as shown in Figure 1. A
moveable-bed beach made of quartz sand, constructed on top of a concrete fixed-
bed beach, is located in the central region of the facility. Four synchronized
wave generators are located offshore to generate unidirectional, long-crested
waves. A rubble mound wave absorber is located behind the wave generators to
minimize wave reflections. Longshore current and sediment are transported
toward the 20 flow channels at the downstream end of the facility (left side of
figure). Each of the 20 flow channels at the downdrift end contains a low profile,
gravity-feed sediment trap to measure the rate of longshore sediment transport.
The longshore current is externally recirculated from the downdrift end of the
facility through 20 independent pump-and-piping systems, back to the upstream
end of the facility (right side of figure). The flow is guided from the discharge
locations to the updrift end of the beach by 20 flow channels at the upstream end
of the facility. The longshore current recirculation system is essentially a closed-
loop system that continuously recirculates longshore current from the
downstream to the upstream lateral boundary of the beach while waves are being
generated.
This chapter provides a brief overview of the various components of the
facility. The external longshore current recirculation system and the sediment
trapping and handling system will be discussed in subsequent chapters because of
the complexity and large number of components in these two systems. Figure 2
is a photograph of the LSTF taken during a recent moveable-bed sediment
transport experiment. The offshore wave conditions during this experiment are
Hs = 0.30 m and Tp = 3.0 sec with a 10-deg angle of wave incidence.
3
Chapter 2
Overview of the Laboratory Facility
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