Detached Eddy Simulation of High-Lift Wing Slat Track and Cut-Out Noise

Detached-eddy simulation is carried out to investigate the unsteady flow in the slat cove and its impact on high-lift device (HLD) noise. Simulations were run for two HLD configurations: a baseline case of a 1/8th scaled clean three-element HDL model, and a configuration adding a slat track and a cut-out on the main element leading edge. Results showed that existence of the slat track system increases the noise sources on the slat surfaces. High intensity turbulent fluctuations on the slat track and cut-out surfaces lead to an increase of noise sources in the slat cove region. Interaction of the shear layer from the slat cusp with the slat track system and interaction of the cut-out vortical flow with the slat wake are identified as the two mechanisms for flow-induced noise due to the added-on slat track elements. Passive measures such as acoustic treatment using sound absorbing materials to the track and cut-out surfaces can reduce the potential noise sources. Geometric modification of the cut-out with a more streamlined main element leading edge can reduce the interaction. Simulations showed that sealing the cut-out can decrease the overall noise levels with dominant noise peaks also shifting towards high frequencies.