What is supercavitation?
What is Supercavitation?
Cavitation is defined as the forming of a vacuum, or pocket of air, by a solid object moving at high speeds through liquid. The term is widely used in the military field when discussing submersible objects that are transported underwater, such as submarines and torpedoes. Supercavitation is the idea that if this bubble of air can be sustained over great distances, that the rapidly moving object inside—doing speeds in excess of 100 mph—can almost fly underwater due to the decrease in water pressure at such speeds.
The design of such vehicles and weapons is very unique, as the body of the object is streamlined to reduce drag, yet the nose of the device is usually rough, flat or barbed to disturb the flow of water enough to create the umbrella-like bubble effect.
The principle of supercavitation as a means of high-speed propulsion was first reported after World War II by Germany, and later by Russia. Since that time, there have been numerous countries vying for new breakthroughs and experimenting with various uses for this technology. Though supercavitation is looked upon as a way to revolutionize underwater transportation, for the most part, advancements in this field for large vehicles such as submarines, have not materialized. The success that creators have had is limited to torpedo and bullet-size projectiles, many of which have been put to small-scale use in missions such as deep underwater clearin of mines.
The downside to this endeavor is that any object reaching the point of supercavitation would ultimately emit large amounts of noise, rendering useless the military advantage of surprise as such noise could easily be picked up by radar and other monitoring instruments.
Supercavitation is a remarkable technology which most people have never heard of. By reducing drag on submarines and torpedoes by a factor of 60-70%, supercavitation could transform the stealthy world of submarine warfare into something more like aerial combat, with objects flying back and forth at speeds much faster than the submarines we know. Supercavitation exploits the phenomena of cavitation, something that submarine designers usually try to avoid. It would work as follows. When the nose of a torpedo or submarine is shaped in a certain way, usually flat with sharp edges, it creates an excessive amount of drag through the water. But the design of the nose accelerates the water it moves through at quick speeds, causing it to lose pressure and vaporize into bubbles. This follows from the well-known Bernoulli’s principle, which states that fluid velocity and pressure/density are related. When the velocity increases, the density drops. When the density drops below the vapor pressure o
