| The international civil aeronautics industry was challenged to increase annual fuel efficiency by 2% between 2010 and 2020. To reach this goal, important investments have to be made in technological operational development. The aircraft drag reduction represents a significant part of the development, especially with promising laminar flow control technologies. Since aircraft construction technologies (smooth surface) and flight altitudes (clean flow) allow a laminar boundary layer on flight surfaces, technologies have been developed to reduce the friction drag by extending the laminar flow regions. Natural laminar flow airfoils have been designed, and wings with suction systems have been tested. This dissertation presents another laminar flow control method, the adaptable wall technology. The technological concept consist of replacing some of the rigid part of the wing by a flexible skin geometrically modified by actuators connected to a real time controller capable of optimizing the airfoil shape according to the flight conditions. The study is limited to a two dimensional wing section and subsonic wind speed. The originality of this work is that it integrates all technologies required for shape control in an aeroelastic research wing to be tested in a wind tunnel. This dissertation introduces the morphing vehicle concept, it exposes geometrical optimization and multidisciplinary optimization integrating an aerostructural model of the wing, and finally, it presents wind tunnel results. The conclusion of the dissertation is that the position of the laminar to turbulent transition point can be controlled with a flexible wall technique. However, the gain provided by the adaptable wing is relatively low when compared to a specifically optimized rigid wing, mostly because the domain is restricted to subsonic speed and to a narrow interval of angle of attack (1 to 2 degrees). |
