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.
Read more about Eddies: Mesoscale Ocean Eddies
Famous quotes containing the word eddies:
“Well, Pa, a woman can change better than a man. A man lives, sort of, well, in jerks. A baby’s born or somebody dies and that’s a jerk. He gets a farm or loses it and that’s a jerk. With a woman, it’s all in one flow, like a stream. Little eddies and waterfalls, but the river, it goes right on. A woman looks at it that way.”
—Nunnally Johnson (1897–1977)
“There sighs, lamentations and loud wailings resounded through the starless air, so that at first it made me weep; strange tongues, horrible language, words of pain, tones of anger, voices loud and hoarse, and with these the sound of hands, made a tumult which is whirling through that air forever dark, as sand eddies in a whirlwind.”
—Dante Alighieri (1265–1321)
“The elaborate star-light throws a reflection
On the dark stream,
Till all the eddies gleam;
And thereupon there comes that scream
From terrified, invisible beast or bird:
Image of poignant recollection.”
—William Butler Yeats (1865–1939)