Why do you get diamond shapes in afterburners?
2006-06-14 02:40:14 · 3 answers · asked by Master_Of_The_Web 2 in Science & Mathematics ➔ Physics
Such a pattern (sometimes called "shock diamonds") is linked to the convergent flow pattern that occurs when exhaust gases exit an overexpanded nozzle. With ideal nozzle expansion, exhaust gas pressure matches the ambient pressure. Nozzles may operate in an overexpanded mode if they are optimized for lower pressure (higher altitude) operation than the current altitude. See the reference for a fuller explanation.
2006-06-14 03:29:53 · answer #1 · answered by kirchwey 7 · 2⤊ 0⤋
Supersonic airflow from the jetstream ( from the afterburner) hits subsonic air flowing over the aircraft.This appears to act as a 'wall' to the wavefront which is reflected back into the centre of the jetstream and bounces on down away from the aircraft.
2006-06-14 02:46:54 · answer #2 · answered by howlingengines 4 · 0⤊ 0⤋
Because the gases are leaving the exhaust at speed due to combustion, and this creates a long flame. It's just like a match, but put under pressure.
2006-06-14 02:46:25 · answer #3 · answered by ? 3 · 0⤊ 0⤋