page_title: Smoke ring
hierarchical_section_title: Smoke ring
caption_attribution_description: English: As a U.S. Special Forces Soldier counts down, his fellow Soldier with Special Operations Task Force - Central fires a Carl Gustav Recoilless Rifle during a training exercise conducted in Basrah, Iraq, May 2, 2009.
context_page_description: A smoke ring is a visible vortex ring formed by smoke in a clear atmosphere.
  Smokers may blow smoke rings from the mouth, intentionally or accidentally. Smoke rings may also be formed by sudden bursts of fire, by shaking a smoke source up and down, by firing certain types of artillery, or by the use of special devices, such as vortex ring toys. The head of a mushroom cloud is a large smoke ring.
  A smoke ring is commonly formed when a puff of smoke is suddenly injected into clear air, especially through a narrow opening. The outer parts of the puff are slowed by the still air relative to the central part, imparting it the characteristic poloidal flow pattern.
  The smoke makes the ring visible, but does not significantly affect the flow. The same phenomenon occurs with any fluid, creating vortex rings which are invisible but otherwise entirely similar to smoke rings.
context_section_description: A smoke ring is a visible vortex ring formed by smoke in a clear atmosphere.
  Smokers may blow smoke rings from the mouth, intentionally or accidentally. Smoke rings may also be formed by sudden bursts of fire (such as lighting and immediately putting out a cigarette lighter), by shaking a smoke source (such as an incense stick) up and down, by firing certain types of artillery, or by the use of special devices, such as vortex ring toys.  The head of a mushroom cloud is a large smoke ring.
  A smoke ring is commonly formed when a puff of smoke is suddenly injected into clear air, especially through a narrow opening.  The outer parts of the puff are slowed by the still air (or by edges of the opening) relative to the central part, imparting it the characteristic poloidal flow pattern.
  The smoke makes the ring visible, but does not significantly affect the flow.  The same phenomenon occurs with any fluid, creating vortex rings which are invisible but otherwise entirely similar to smoke rings.
caption: Smoke rings are also emitted by various types of weapons.
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