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

According to the report, the pilot from the day’s earlier training flight described being surprised that the instructor did not intervene when, after instructing the pilot to perform a vortex ring state recovery maneuver, the helicopter developed a very high descent rate.

From Seattle Times

“The accident was attributed to a little-understood flight phenomenon called vortex ring state, or VRS, in which a helicopter descending rapidly at low forward speed drops into its own turbulence,” according to a report from Wired magazine.

From Washington Times

The researchers found that the jellyfish create a vortex ring in the water underneath their bells after each thrust forward, generating higher pressure below that they can more efficiently push off of with their next move.

From Science Magazine

Philadelphia aviation lawyer Arthur Alan Wolk, who represents the families, said Cullen was an “expert in vortex ring state avoidance and the Bell 407 he was flying is virtually impossible to suffer from that phenomenon.”

From Washington Post