Width of the area affected by fetch (at a right angle to the distance).The uninterrupted distance of open water over which the wind blows without significant change in direction (called the fetch).Wind speed or strength relative to wave speed – the wind must be moving faster than the wave crest for energy transfer.Five factors influence the formation of the flow structures in wind waves: The great majority of large breakers seen at a beach result from distant winds. NOAA ship Delaware II in bad weather on Georges Bank The key statistics of wind waves (both seas and swells) in evolving sea states can be predicted with wind wave models.Īlthough waves are usually considered in the water seas of Earth, the hydrocarbon seas of Titan may also have wind-driven waves. They can be described as a stochastic process, in combination with the physics governing their generation, growth, propagation, and decay – as well as governing the interdependence between flow quantities such as: the water surface movements, flow velocities and water pressure. Wind waves have a certain amount of randomness: subsequent waves differ in height, duration, and shape with limited predictability. Wind waves in the ocean are also called ocean surface waves, and are mainly gravity waves, where gravity is the main equilibrium force. They have been generated elsewhere and some time previously. Swell consists of wind-generated waves that are not significantly affected by the local wind at that time. A noteworthy example of this is waves generated south of Tasmania during heavy winds that will travel across the Pacific to southern California, producing desirable surfing conditions. After moving out of the area of fetch, wind waves are called swells and can travel thousands of kilometers. Wind waves will travel in a great circle route after being generated – curving slightly left in the southern hemisphere and slightly right in the northern hemisphere. When directly generated and affected by local wind, a wind wave system is called a wind sea. Wind waves on Earth range in size from small ripples, to waves over 30 m (100 ft) high, being limited by wind speed, duration, fetch, and water depth. Waves in the oceans can travel thousands of kilometres before reaching land. The contact distance in the direction of the wind is known as the fetch. In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. Although sea turtles are the first animals shown to be capable of detecting wave direction in this way, such an orientation mechanism may be widespread among other transoceanic migrants such as fish and cetaceans.Video of large waves from Hurricane Marie along the coast of Newport Beach, California The results demonstrate that hatchling sea turtles can determine the propagation direction of ocean waves by monitoring the circular movements that occur as waves pass above. Movements simulating waves from directly in front of the turtles elicited little turning in either direction. Hatchlings suspended in air and subjected to movements that simulated waves approaching from their right sides attempted to turn right, whereas movements that simulated waves from the left elicited left-turning behavior. To determine whether loggerhead (Caretta caretta L.) and green turtle (Chelonia mydas L.) hatchlings can detect wave direction in this way, we constructed a wave motion simulator to reproduce in air the circular movements that occur beneath small ocean waves. In principle, swimming turtles might, therefore, detect wave direction by monitoring the sequence of accelerations they experience under water. Objects in a water column beneath the surface of the ocean describe a circular movement as waves pass above. How turtles can detect wave direction while swimming under water in darkness, however, has not been explained. At the beginning of their offshore migration, hatchling sea turtles enter the ocean at night and establish a course away from land by swimming directly into oceanic waves.
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