SUPERSONIC INTAKE

For this speed range, we need to redesign the intake as the simple pitot type intake is no good above Mach 1.2.

A normal shock wave on its own is not a good idea due to the sudden energy change it produces which merely creates heat energy at the expense of pressure.

What we really need is 2 shock waves, one oblique to take the air velocity down to a value acceptable value and a normal shock.

At very high Mach numbers, we may have to utilize several oblique waves to achieve the necessary gentle deceleration down to the normal shock entry.

Variable diameter supersonic inlet at high supersonic speed
Variable diameter supersonic inlet at high supersonic speed

Early supersonic intake consisted of a pitot type duct with a movable spike shaped bullet, which both created the necessary oblique and normal shocks and created a convergent/ divergent duct.

Diffusion occurs first through the oblique wave, reducing the air velocity down to a lower supersonic value.

The air then passes through the converging part of the intake where it behaves as supersonic flow and slows whilst increasing in pressure.

After passing the normal shock the air then behaves as subsonic flow in the divergent section of the duct and slows further whilst still increasing its pressure.

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