vortex ring

British  

noun

1. a stable perturbation in a fluid that takes the form of a torus in which the flow rotates in the section of the torus so that the pressure difference between the inside and outside of the torus balances body forces. The best-known vortex ring is a smoke ring

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Example Sentences

In a report issued Dec. 8, investigators cited the pilots’ “inappropriate flight control inputs” while practicing for an unstable condition known as vortex ring state.

From Seattle Times • Dec. 13, 2023

The technicians immediately identified the UFO as a vortex ring formed when diesel oil, gasoline and white phosphorus was exploded by TNT to simulate atomic-bomb explosions during demonstrations.

From Time Magazine Archive

A tap on the canvas will cause a vortex ring to start from the hole; and if the box be filled with smoke, this ring will be visible for many feet of its path.

From The Story of the Heavens by Ball, Robert S. (Robert Stawell), Sir

Dr. Larmor suggests that a vortex ring may have this constitution in his work on Aether and Matter.

From Aether and Gravitation by Hooper, William George

Thus the compound formed will be the simplest combination, consisting of one of the atoms which consist of two vortex rings linked together with two of the atoms consisting of only one vortex ring.

From Aether and Gravitation by Hooper, William George