Noise from high-lift leading-edge device

Noise generation from the leading edge system of the aircraft is based on features of the flow in the slat region. Unsteady flow near the slat excites the flow field including mechanisms responsible for noise radiation. Flow separation at the slat cusp, creation of flow vertical system in the slat cove region, and disturbances in the gap between the slat and the main element all cause an acoustic radiation. Time-accurate Unsteady Reynolds Averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) computations have been used to resolve the transient flow field. The dynamic features of the flow that create slat noise mechanisms are fairly predicted and resolved. For the acoustics the Ffowcs-William and Hawkings (F-WH) equation is solved through the solver (RANS/LES) to capture the acoustic signal at the slat. Acoustic spectra have been plotted in regard to angle of attack variations.