What are the rings in afterburner?

Those are known as “Mach diamonds” or “Shock diamonds” (and a number of other names) and are not a characteristic of the afterburner per se but are formed by standing waves in the exhaust when the pressure of the expanded exhaust gases do not exactly match external ambient pressure.

What causes the rings in afterburner?

As the exhaust passes through the normal shock wave, its temperature increases, igniting excess fuel and causing the glow that makes the shock diamonds visible. The illuminated regions either appear as disks or diamonds, giving them their name.

What does an afterburner do on a jet?

An afterburner (or a reheat) is an additional component present on some jet engines, mostly military supersonic aircraft. Its purpose is to provide an increase in thrust, usually for supersonic flight, takeoff and for combat situations.

What is a Mach ring?

The pattern of evenly spaced rings sometimes visible in the exhaust of an engine is typically referred to as shock diamonds or Mach disks. The phenomenon occurs anytime a flow exits a nozzle at supersonic speeds and at a pressure that is different than that of the external atmosphere.

Are Mach diamonds good?

Seeing mach diamonds is pretty awesome, and looks very cool, but the reason they exist in the first place is because a pressure mismatch from nozzle exit to atmospheric pressure. This means that the nozzle expansion is inappropriately sized for delivering maximum thrust/efficiency at that pressure (altitude).

Are afterburners effective?

The big advantage of an afterburner is that you can significantly increase the thrust of the engine without adding much weight or complexity to the engine. An afterburner is nothing but a set of fuel injectors, a tube and flame holder that the fuel burns in, and an adjustable nozzle.

Are mach diamonds good?

Why do Mach diamonds occur?

In case you’re unfamiliar, shock diamonds, also called mach diamonds or mach disks, occur when jet exhaust travels faster than the speed of sound in atmosphere. Due to complex factors, supersonic exhaust tends to exhibit repeating wave patterns, as seen in this video: This content is imported from YouTube.

What is oblique shock wave?

Depending on the shape of the object and the speed of the flow, the shock wave may be inclined to the flow direction. When a shock wave is inclined to the flow direction it is called an oblique shock.