Aeroacoustic mechanisms and multi-objective optimization of variable camber airfoils for noise reduction

High-lift devices are dominant sources of airframe noise during approach and landing due to the geometric discontinuities inherent in traditional slotted flaps. The integrated aerodynamic and aeroacoustic performance of morphing trailing-edge airfoils is investigated to mitigate these aeroacoustic disturbances. A compact Akima curve based cubic parameterization is used to generate smooth morphing trailing edge profiles with prescribed endpoint and tangent constraints. Large-eddy simulations (LES) coupled with the Ffowcs Williams-Hawkings (FW-H) equation are employed to examine the comparative noise-generation mechanisms, with the plain-flap and hinged-flap airfoils serving as fixed baselines. Within the present two-dimensional sectional framework, the morphing trailing-edge airfoil reduces OASPL by 3–19 dB across the examined directivity angles relative to the plain-flap baseline. Spectral analysis further indicates that the continuous trailing-edge structure primarily attenuates mid-to-high-frequency noise, consistent with improved unsteady-shear-layer stability. To balance aerodynamic efficiency with noise suppression, a comprehensive database of 491 configurations was established for multi-objective optimization through Pareto front screening. Within the prescribed discrete design space, the selected high-lift configuration increases the lift coefficient by 30.2% while reducing noise by 8.6 dB relative to the hinged-flap baseline. These findings characterize the sectional aerodynamic–acoustic benefits of morphing structures and may inform the development of morphing high-lift devices for future low-noise aircraft.