| This doctoral research contributed to the success of the project CRIAQ 7.1, demonstrating the capability of a morphing laminar wing to reduce fuel consumption. Respectively, this thesis shows the design of the experimental wing and its operation in a subsonic wind tunnel (Mach numbers of 0.2 to 0.3 with angles of attack between -1 and 2°).;Thereafter, the research effort focused on the exploitation of the morphing capabilities of the experimental wing over each given set of flow conditions. Therefore, once the prototype was built, the structural model was refined, calibrated and coupled with the aerodynamic solver to accurately predict the aero-structural behavior in the wind tunnel. Optimal morphing wing shapes were numerically calculated using a generalized pattern search algorithm and a local search routine to refine the solution. In the wind tunnel, this open-loop control approach allowed an average 25% laminar flow regime extension over the wing prototype upper surface. Consequently, an average 18.5% profile drag reduction was measured by the pressure survey rake across the wake.;Although these results were satisfactory, limitations in the aero-structural coupled model were observed when comparing numerical and experimental responses of the prototype. For that reason, the research continued with the development of a real-time optimization strategy in closed loop to exploit the complete potential of the morphing laminar wing. The wind tunnel balance was used as a hardware-in-the-loop returning the instantaneous lift-to-drag ratio to the optimizer. An optimization algorithm has been built to minimize the actuation required and thus reduce the time period until convergence to the optimal shape. To accelerate the search, numerically predicted actuation strokes (open loop) were used as initial modified shapes. As measured in the wind tunnel, the use of the closed-loop control strategy resulted in an average lift-to-drag ratio increase from 11 to 12.2% as compared to the open-loop approach. No more than 4 additional minutes were required to converge to the real-time optimized shapes, an acceptably small time delay on the cruise flight period time scale. Finally, infrared measurements performed byt the IAR-NRC team allowed experimental demonstration of the reciprocity between the laminar flow improvement and the lift-to-drag ratio increase.;Keywords: morphing laminar wing, finite elements, design, active structure, composite structure, wind tunnel tests, multi-objective optimization, real-time optimization, actuators, shape memory alloy.;First of all, the morphing wing is formed of a composite laminate linked to an actuation system to build an active structure capable of modifying the wing upper surface geometry. The design was performed using a new developed methodology to solve aero-structural problems. Using ANSYS software, the finite elements method was applied to model the different possible active structure configurations Aerodynamic loads applied over the active structure as well as targeted morphed geometries have been provided by the Ecole Polytechnique team. Next, laminar flow enhancements allowed by each active structure configuration we' re evaluated using the aerodynamic solver XFoil 6.96. A best trade-off between aerodynamic performance and energy needed for wing morphing was found using a multi-objective optimization technique. Among the retained stable configurations, a 4-ply composite laminated shell driven by 2 actuation lines was retained. |
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