Aerodynamic performance optimization of a wind tunnel morphing wing model subject to various cruise flow conditions

A large-scale multi-disciplinary research project, CRIAQ 7.1, was undertaken to investigate a morphing wing concept for aircraft aerodynamic performance improvement over various flow conditions. The collaborators were Ecole de Technologie Sup\ue9rieure of Montreal (ETS), Ecole Polytechnique of Montreal (EP), Bombardier Aerospace (BA), Thales Avionic Inc. (Thales) and the National Research Council of Canada (NRC). The project was mainly funded by the Consortium for Research and Innovation in Aerospace in Quebec (CRIAQ). The main objective of the morphing concept was to reduce drag by improving the extent of laminar flow on the wing surfaces, by delaying transition toward the trailing edge. The wing consisted of rigid and flexible parts, and smart material alloy actuators. The investigation was based on numerical simulations and wind tunnel tests. The simulations involved the wing-upper surface shape optimization for various cruise flow conditions, the design of the wing and its morphing skin, the design and development of the smart actuators, and the controllers. Three types of controllers were built, following three approaches. The first controller was based on experimental pressure signal data recorded on the wing morphing skin surface. The second controller was supplied the wing aerodynamic loads (lift L and drag D). In the third controller, the transition location on the wing, determined by infrared measurements, was used as input. The three controllers\u2019functionality was demonstrated during bench tests, at ETS (wind off), and in the wind tunnel (wind off and on) at NRC. Their performance and behavior seemed to differ but yielded approximately the same expected wing aerodynamic performance improvement. A 30% reduction in the wing drag was achieved. In the present paper, the three controllers and their operability are discussed briefly, followed by athorough experimental validationof the controllers and wing shape optimizers. Also, wind tunnel data in terms of pressure signals, wing aerodynamic loads and infrared measurements are analysed for various flow conditions and optimal wing shapes. Emphasis is placed on the effect of the optimized wing shapes on the wing drag reduction. The results are presented in terms of measured and computed pressure coefficient profiles, wing loads (drag and lift), controller performance and optimizer efficiency.Peer reviewed: NoNRC publication: Ye