What are those dented edges some aeroplane engines have on their rear ends? Have you ever seen them? Have you ever asked yourself what they’re for?
You already know the aviation world is always investigating sustainability and trying to make aeroplanes quieter, don’t you?
In today’s post we explain the new design being used by manufacturers of aeronautical engines: chevrons.
To understand their function, one must first grasp the origin of noise in a turbofan engine. The most intense sound comes from the turbulent mixing of three air currents at vastly different speeds and temperatures, all converging at the exit:
The resulting roar is the effect of the violent shear between these layers. The role of the chevrons is to introduce small, controlled vortices at the edge of this mixing point.
These vortices promote a more orderly and progressive merger of the airflows, thereby reducing turbulence and, as a result, the intensity of the noise.
Although Boeing was a key player in their development, chevrons are now an industry standard. They can be found on:
