08-04-2010, 11:37 AM
Supercavitation is the use of cavitation effects to create a large bubble of gas inside a liquid, allowing an object to travel at great speed through the liquid by being wholly enveloped by the bubble.Current applications are mainly limited to very fast torpedoes.
basics
Cavitation happens when water pressure is lowered below its vapor pressure or vapor pressure is increased to water pressure. The pressure of the fluid can drop due to its high speed (Bernoulli's principle) and when the pressure drops below the vapor pressure of the water or the temperature increases thus vapor pressure increases reaching water pressure, it vaporizes “ typically forming small bubbles of water vapour (water in its gas phase).
applications
used for very high performance propellers and also for control surfaces such as rudders.
In 2004, German weapons manufacturer Diehl BGT Defence announced their own supercavitating torpedo, Barracuda
RAMICS (Rapid Airborne MIne Clearance System), based on a supercavitating projectile stable in both air and water.
Iran has claimed to have successfully tested its first supercavitation torpedo.
The Kursk submarine accident is rumored to have been due to a faulty Shkval torpedo
advantages
Comparing the efficiency of the different methods of the hydrodynamic drag reduction with efficiency
of the artificial and vapor supercavitation, one can see its advantage.
Reduction of water adhesion to the surface or slippage;
-Effect of the movable surface (the gas flow velocity in the clearance may be equal to the water flow
velocity);
- Change of the physical constants of BL (here, the medium density reduction);
- Gas blowing into the boundary layer (BL).
Here, - in the case of the artificial cavitation, the gas is blown through the solid surface of the object.
for details visit:
http://en.wikipediawiki/Supercavitation
for details visit:
http://en.wikipediawiki/Supercavitation
basics
Cavitation happens when water pressure is lowered below its vapor pressure or vapor pressure is increased to water pressure. The pressure of the fluid can drop due to its high speed (Bernoulli's principle) and when the pressure drops below the vapor pressure of the water or the temperature increases thus vapor pressure increases reaching water pressure, it vaporizes “ typically forming small bubbles of water vapour (water in its gas phase).
applications
used for very high performance propellers and also for control surfaces such as rudders.
In 2004, German weapons manufacturer Diehl BGT Defence announced their own supercavitating torpedo, Barracuda
RAMICS (Rapid Airborne MIne Clearance System), based on a supercavitating projectile stable in both air and water.
Iran has claimed to have successfully tested its first supercavitation torpedo.
The Kursk submarine accident is rumored to have been due to a faulty Shkval torpedo
advantages
Comparing the efficiency of the different methods of the hydrodynamic drag reduction with efficiency
of the artificial and vapor supercavitation, one can see its advantage.
Reduction of water adhesion to the surface or slippage;
-Effect of the movable surface (the gas flow velocity in the clearance may be equal to the water flow
velocity);
- Change of the physical constants of BL (here, the medium density reduction);
- Gas blowing into the boundary layer (BL).
Here, - in the case of the artificial cavitation, the gas is blown through the solid surface of the object.
for details visit:
http://en.wikipediawiki/Supercavitation
for details visit:
http://en.wikipediawiki/Supercavitation
