The super-cavitation is a case of cavitation, in which flow around very quickly from behind a body of liquid ( cavitator ) so greatly reduced by the predatory impulse of the pressure that the liquid passes its phase diagram, following in the vapor phase. In this ellipsoid gas-filled region ( cavity or cavern called ), for example, a very large in comparison to the cavitator object with a very low flow resistance through the liquid. After assessments Soviet researchers an under water in a super-cavitation moving subject from about 300 m / s to a lower flow resistance subject than for a same speed of movement in the air, under the condition that the moving in the body of air having the same cross-section as the cavity. The speed of forming a super-cavitation 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, a functioning system that uses the supercavitation, 1977 the torpedo Shkval was put into service after ten years of development by the Navy of the Soviet Union. Its speed is specified between 350 and 500 km / h. It is driven by a solid rocket motor.
One problem with the movement in a super-cavitation is the controllability, as early models of the Shkval was unguided. There but various control concepts have been developed since then, so rotate the current versions of the Shkval probably about its longitudinal axis and are thus controlled by means of a pivotable about an axis cavitator.
The German Navy has developed together with the technology company Diehl BGT Defence to " supercavitating underwater running body ", a novel high -speed torpedo. This torpedo is specified by the manufacturer under water not only over 400 km / h (about 216 knots ), but also steerable.
Underwater projectiles also make use of the super-cavitation. They build without technical aids around a full bladder around.