Dictionary Meaning and Definition on 'Eddies'
- Eddy \Ed"dy\, n.; pl. Eddies. [Prob. fr. Icel. i?a; cf. Icel.
pref. i?- back, AS. ed-, OS. idug-, OHG. ita-; Goth. id-.]
- A current of air or water running back, or in a direction contrary to the main current.
- A current of water or air moving in a circular direction; a whirlpool. And smiling eddies dimpled on the main. --Dryden. Wheel through the air, in circling eddies play. --Addison. Note: Used also adjectively; as, eddy winds. --Dryden.
Wikipedia Meaning and Definition on 'Eddies'
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid flows past an obstacle. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is most visible behind large emergent rocks in swift-flowing rivers.
Another possible type of turbulence is the vortex. This notion is now applied to gases, which have the same properties as liquids. Here, no void is created, but only an area of lower pressure, but again, a backflow causes the gas to rotate.
Eddies are common in the ocean, and range in diameter from centimeters, to hundreds of kilometers. The smallest scale eddies may last for a matter of seconds, while the larger features may persist for months to years. Those eddies which are between about 10 and 500 km in diameter, and persist for periods of days to months are commonly referred to in oceanography as mesoscale eddies.[See more about Eddies at Dictionary 3.0 Encyclopedia]