Supercavitation

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Cavitation formation behind a body around which fluid flows very quickly
Cavitator of a Shkwal torpedo with gas exhaust ports
Supercavitation bubble around an underwater projectile (superpenetrator)

The supercavitation is a case of cavitation ( lat. Cavus , "hollow"), behind a very fast of at the liquid immersed body (cavitator) by the displacement pulse of the pressure reduced so much that the liquid their phase diagram proceeds following to the vapor phase . In this ellipsoidal gas-filled area (called cavity or cavern ) z. B. compared to the cavitator a very large object with very little flow resistance can be passed through the liquid. According to estimates by Soviet researchers, an object moved underwater in a supercavitation is exposed to a lower flow resistance from around 300 m / s than a movement of the same speed in air , provided that the body moved in air has the same cross-section as the cavity.
The speed for the formation of a supercavitation in water is in the range of 180  km / h , depending on the pressure and the temperature of the water and the shape of the cavitator. First operational system that uses the supercavitation, 1977 was Torpedo Schkwal after about ten years of development of the Navy of the Soviet Union put into service. Its speed is given as 370 km / h. It is propelled by a solid rocket engine .

A problem with moving in a supercavitation is controllability, so early models of the Shkwal were unguided. Since then, however, various control concepts have been developed. Current versions of the Schkwal presumably rotate around their longitudinal axis and can therefore be controlled by means of a cavitator that can be pivoted around an axis.

The German Navy developed together with the consolidated Diehl BGT Defense , the trial project " Superkavitierender underwater running bodies ", a steerable torpedo km / h (about 216 according to the manufacturer 400  kn should reach). It was presented to the public in 2005, but did not get ready for series production.

literature

  • Spectrum of Science 08/2001, rockets under water preview
  • Wunderwelt Wissen 01/05

Web links

Commons : Supercavitation  - collection of images, videos and audio files

Individual evidence

  1. ↑ Science and Humanity 1987, Urania Verlag
  2. ↑ Gerhard Hegmann: Cross the Atlantic in under an hour? In: Welt.de of July 3, 2016, accessed on March 16, 2017.