Aeroacoustics in aeronautics

Even though aircraft noise affects only a small proportion of the population, it is extremely annoying, as it manifests itself through the more or less random occurrence of brief, very loud events. Reducing it is one of the priorities of air transport, so that it can continue to develop in harmony with local residents.

The article begins by recalling that the foundations of aeroacoustics were laid by Lighthill as early as 1952, but that the numerical integration of the equations is still in its infancy. On the other hand, the physical laws of aeroacoustics have long been well understood, notably the preponderant effect of speed on noise levels. The next paragraph focuses on acoustic certification, which is a prerequisite for civil aircraft to be allowed to fly; it shows that this constraint is also a source of progress.

The focus then shifts to commercial jets, as they are the main cause of noise pollution in aeronautics. The origin of the noise is mainly linked to turbojet engines, and the fan in particular. Other types of aircraft are also reviewed: supersonic aircraft, propeller-driven aircraft, helicopters, not forgetting a brief allusion to space launchers. Acoustic sources are listed in each case, along with ways of reducing their radiation.

The conclusion moves on from physiological effects to a few indications on psychoacoustics.