Wind-Generated Waves

Abstract

Synopsis Wind-generated waves are the most important energy input into the littoral zone and, together with wave-generated currents, they are responsible for coastal erosion and sediment transport. They are thus the primary force leading to modification of the coast and the creation of erosional and depositional landforms A wind wave is simply a vertical displacement of the surface of a body of water that results from the transfer of energy from the wind to the water surface. Wind-generated waves are periodic, in that they appear as undulations on the water surface characterised by a high point, or crest, followed by a low point, or trough. They are also progressive in that the wave form travels across the water surface in the direction that the generating wind blows. The energy transferred from the wind is expressed in the potential energy resulting from the displacement of the crest and trough of the wave above and below the original still-water surface, and in the kinetic energy of the circular motion of water particles within the wave. In addition to waves generated by winds, a variety of other waves are found in oceans and lakes ranging from very long period waves, such as the tidal waves generated by the gravitational force of the moon and sun, to waves with much shorter periods, such as the standing waves produced by reflection of wind waves from seawalls.