wavemakers

Wavemakers, or wave makers, are devices used to generate controlled surface waves in tanks and basins for hydrodynamic research, coastal engineering, and the testing of maritime structures. They enable laboratory experiments on wave propagation, runup, breaking, and interactions with structures under scaled conditions.

The most common types are flap-type and piston-type wavemakers. A flap-type device uses a hinged plate that rotates to push water and generate waves, usually in two-dimensional tanks. A piston-type wavemaker moves a vertical plunger to displace water, useful in wider tanks or three-dimensional fields. Some facilities employ multiple actuators to create complex or three-dimensional wave fields.

Wavemakers can produce regular (monochromatic) waves with specified period and height, as well as irregular waves with defined spectra to resemble real sea states. Modern systems are computer-controlled and may combine multiple actuators to create programmable wave histories and irregular wave trains, enabling more realistic testing scenarios.

Applications include testing coastal defenses, breakwaters, offshore structures, ships, and wave energy devices; investigations of wave reflection, runup, and breaking dynamics; and sediment transport experiments. They are essential for validating numerical models and for studying scale effects in hydrodynamic processes.

Practical considerations include minimizing wave reflections at tank boundaries with absorbers and bathymetric shaping, achieving accurate boundary conditions, and maintaining dimensional similarity via scaling laws such as Froude similarity. Design and operation are also limited by tank size, drive capabilities, and the precision required to reproduce target wave conditions.

See also: wave tank, coastal engineering, hydrodynamics.