Intake ramp

[2] At supersonic flight speeds, the deflection of the air stream creates a number of oblique shock waves at each change of gradient along at the ramp.

Air crossing each shock wave suddenly slows to a lower Mach number, thus increasing pressure.

For a fixed geometry intake at zero incidence, this condition can only be achieved at one particular flight Mach number, because the angle of the shock wave (to the longitudinal direction) becomes more acute with increasing aircraft speed.

More advanced supersonic intakes feature a ramp with a number of discrete changes of gradient in order to generate multiple oblique shock waves.

This intake design thus ensures excellent pressure recovery and contributes to Concorde's improved fuel efficiency whilst cruising supersonically at up to Mach 2.2 (beyond which airframe heating effects limit any further increase in speed).