Aeroacoustic Effects of High-Lift Wing Slat Track and Cut-Out System

Abstract

Effects of the slat track and cut-out on noise propagation were investigated using compact source models for a high-lift wing. Two different geometries of the high-lift devices, with and without the slat track and cut-out, were investigated. Convection effects were also considered with the mean flows obtained from precursor simulations of corresponding high-lift configurations. Major noise sources in the slat cove region were modelled with equivalent compact dipoles placed along the slat trailing edge and cusp. Results show that sound propagation is modified by the add-on components. The acoustic waves are amplified significantly and radiate more energy towards the ground due to the interaction between propagating waves and the slat track and cut-out. Although the cancellation caused by interference of the radiated and reflected waves happens in both of these configurations especially in the downwards direction, it is more prominent once sound waves pass the slat track and cut-out. Wave cancellation is also significant when the wavelength is comparable to the size of the barrier such as the gap between the slat and the main element. It is also noticed that higher frequencies radiate large proportion of energy towards ground for the sources at slat cusp.