Landing gears aerodynamic interaction noise

Abstract

Airframe noise is generated as a result of the interaction of turbulent flow with different airframe components, i.e. the high lift devices and landing gears in particular, and may dominate over engine noise in the approach phase of large commercial aircraft. This paper describes the landing gears interaction noise research work in the EC co-financed project "Significantly Lower Community Exposure to Aircraft Noise" (SILENCER). Systematic steady and unsteady landing gear wake measurements were performed on differently scaled A340 type centre and main landing gears. The analysis of wake measurements showed almost isotropic turbulence characteristics for short distances downstream. Noise measurements were performed for a main landing gear being exposed to the wake flow of a centre landing gear. It turned out that only low frequency interaction noise is likely to be radiated while at high frequencies a noise reduction is obtained due to reduced mean wake flow speed.