Shock diamonds or mach diamonds 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 gasses 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 the visible diamond-shaped pattern that gives the shock diamond its name is formed.

External links

• http://www.aerospaceweb.org/question/propulsion/q0224.shtml

See also

• Shock wave