7
Wave Generation and
Current Recirculation
Introduction
This chapter contains two major sections. The first section deals with the
subject of generating waves in the facility, and specifically describes the
procedures used to: (a) calibrate the wave generators; (b) synthesize regular and
irregular wave drive signals; (c) synchronize the wave generators to create
unidirectional long-crested waves; and (d) generate waves using a new drive
signal. The second section deals with the subject of recirculating the longshore
current using the longshore current recirculation system described in detail in
Chapter 3. This section specifically describes the procedures used to:
(a) calculate the required pump discharge rates after the cross-shore distribution
of the depth-average longshore current to be recirculated has been determined;
and (b) set the speed of the pumps to achieve the required discharge rates from
the 20 vertical turbine pumps. This chapter provides a conceptual overview of
these procedures.
Wave Generation
All of the programs discussed in this section can be found in the "2D
Random Wave Generation" category of the GEDAP analysis package. The
location of this category with respect to the overall structure of the GEDAP
system was shown previously in a block diagram in Figure 36. For several of the
procedures discussed below, GEDAP batch files were created to simplify and
standardize the procedure to maintain consistency from one experiment to the
next.
Calibration of wave generators
The wave generators are calibrated by using a static calibration drive signal
that is generated using program RWREP5, an acronym for Random Wave
Reproduction. This calibration signal is used to slowly and smoothly move the
four wave boards from zero to full forward stroke and then to full reverse stroke.
The wave boards are held steady at the full forward, and the full reverse stroke
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Chapter 7
Wave Generation and Current Recirculation
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