Smoke ring

A smoke ring is a visible flow phenomenon in the air. It occurs relatively rarely and is mostly produced by human activities, but also by volcanoes.

A smoke ring is caused by vortex formation in the form of a torus with flow direction around the ring body. The phenomenon has a very low self-motion, which is substantially along the axis of the ring. However, the internal speeds are much stronger, form a self- flow and thus the energy system. While the turbidity in the area usually loses quickly, the smoke particles of the ring are quasi included. Such a ring, for example, a size of about 10 m are at a ring thickness of about 60 cm. These parameters are relatively constant, at most a certain extent increase is recorded by observers at the beginning. Depending on the ambient air, such a ring are maintained for several minutes.

Smoking can with some practice produce such rings, especially a nearly circular mouth opening is required. In addition, ejected a small amount of air through gentle movement of the jaw, tongue, or lungs. The first smoke usually located in the lung is only used for visualization of the result.

Typical situations where smoke rings occur are:

• Targeted exhalation of a smoker
• For explosion -like, directed explosions, eg the fire-eating
• Occasionally in a nuclear explosion

The selective reproduction of this vortex can be accomplished by a so-called ring of smoke chamber. Here, a cube-shaped room usually made ​​of light wood or cardboard is coated on one side in the middle with a hole and enriched the cube volume with smoke. Sudden, jerky beating on the side of the hole opposite surface results in an excess pressure which of course escapes through the hole. By flowing from all sides to the edge of air inevitably results in a very uniform velocity at the hole edges. This results with a certain probability and depending on the other parameters to form a smoke ring. A less expensive method is the use of a 1.5 liter PET bottle, which ejects through targeted rapid impressions in the smoke- filled state with high probability one or even several smoke rings.

A similar effect can also be accomplished by divers under water, in which case air bubbles are formed annularly and then ascend to the surface. Even with dolphins, such an effect has been observed in isolated cases.