Electroactive morphing effects on the aerodynamic performance through wobulation around an A320 wing with vibrating trailing edge at high Reynolds number

Abstract

This study aims to investigate the effects of electroactive morphing on a 70cm chord A320 wing by means of near trailing edge slight deformation and vibration. Wing morphing is performed by Macro Fiber Composites (MFC) mini-piezoelectric actuators distributed along the span of the ''Reduced Scale'' (RS) A320 prototype of the H2020 No 723402 European research project SMS, ''Smart Morphing and Sensing for aeronautical configurations'', (https://cordis.europa.eu/project/id/723402 and www.smartwing.org/SMS/EU). The configuration studied corresponds to a low-subsonic regime (Mach number 0.063) with a 10 degree incidence and a Reynolds number of 1 Million. The numerical simulations are carried out with the Navier-Stokes Multi-Block (NSMB) solver, which takes into account the deformation of the rear part of the wing implemented experimentally with the piezoelectric actuators. A detailed physical analysis of the morphing effects on the wake dynamics and on the aerodynamic performance is conducted with a constant amplitude of 0.7cm over a wide range of actuation frequencies [10-600]Hz. Optimal vibration ranges of [180-192]Hz and [205-215]Hz were found to respectively provide a 1% drag reduction and a 2% lift-to-drag ratio increase compared to the non-morphing (static) configuration. The natural frequencies associated with the shear layer Kelvin-Helmholtz (KH) vortices and the Von-Karman (VK) vortex shedding were found to play a central role in the modification of the wake dynamics by morphing as well as in the increase of the aerodynamic performance. Actuating at (or close to) the upper shear layer (USL) natural frequency (~185Hz) provides an order of 1% drag reduction and 1% lift-to-drag ratio increase, while actuating at (or close to) the lower shear layer (LSL) natural frequency (~208Hz) provides an order of 8% lift increase and 2% lift-to-drag increase. Furthermore, the linear variation of the actuation frequency over time, called wobulation, was shown to have significant effects. This approach demonstrated, through an appropriate mapping, the ability to quickly and efficiently detect optimal constant actuation frequency ranges providing aerodynamic performance increase and simultaneously reducing the amplitude of the main instability modes.