Shock diamonds (also known as Mach diamonds or Mach disks) are a formation of shock waves in the exhaust plume of an aerospace propulsion system, such as a supersonic jet engine, rocket, ramjet, or scramjet. It is formed when the supersonic exhaust from a nozzle is slightly over or under-expanded, meaning that the pressure of the gases exiting the nozzle is different from the ambient pressure. A complex flow field results as the shock wave is reflected at the free jet boundary and a visible diamond-shaped pattern is formed which gives the shock diamond its name.

See also

• Shock wave

External links

• http://www.aerospaceweb.org/question/propulsion/q0224.shtml
• http://science.nasa.gov/headlines/y2007/04may_methaneblast.htm?list208336 Shock diamonds forming in NASA's methane engine