Chapter 7
Laboratory Wave
Generation
“Wave generation capability has evolved from the time when
researchers were completely at the mercy of a limited technology to the present where the capability of wave generators and
computers exceeds the current understanding of wave dynamic
processes.” .. .Ed Funke and Etienne Mansard (1987)
7.1 Introduction
The use of physical models in coastal engineering would be severely limited
if we were unable to create waves in small scale models that exhibited many
of the characteristics of waves in nature. Although wind can be used in a
small scale wave tank to generate waves, the tank must be enclosed and of
sufficient length for the wind to generate the desired condition. A far more
common approach is mechanical wave generation where a movable partition
is placed in the wave facility and waves are generated by oscillation of the
partition.
The earliest wavemakers generated uniform waves by moving the wave
board in a sinusoidal motion with a given amplitude and period of oscillation. Although this was a very simplified approximation of real-world
waves, these simple waves conformed reasonably well to linear wave theory,
and pioneering researchers used this laboratory capability to make great
strides in coastal engineering. Portable wave machines were used (and still
are used) in basin models to provide a train of unidirectional waves with
wave crests parallel to the wave board.