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

If we united three vortex rings, then the result would be an atom of threefold the density and strength of the unit vortex ring.

From Aether and Gravitation by Hooper, William George

We have, then, to consider the atom of any element as being composed of a vortex ring of various thickness, the thickness of the ring being an indication of its atomic weight.

From Aether and Gravitation by Hooper, William George

The experimenter should notice how a vortex ring rotates in itself while moving forward, like a rubber ring being rolled along a stick.

From Things To Make by Williams, Archibald