Experimental investigation of morphing wing aerodynamics by force measurements and particle image velocimetry

Özçakmak, Özge Sinem
Recently, new developments in on manufacturing technologies, aircraft materials, sensors, actuators, and other mechanisms raised the interest in morphing wings. Instead of conventional wings, which are optimized only for one flight condition, morphing wings can adapt themselves for different missions, mission segments and associated flight conditions. The focus of this thesis is the experimental analysis of a morphing wing, the planform and airfoil shapes that were made available from a separate numerical study. Four half wing models, one of which is the base model, are manufactured separately and load cell measurements are performed in order to obtain the lift and drag values of these wings for seven velocity and twenty angle of attack values. The physical behavior of the flow is analyzed by performing oil flow visualization technique for one of the models and compared with the load cell experiments. According to the load cell measurements in level flight, for a fixed value of lift, the angle of attack and the drag trends of the wings are analyzed. Then, at these velocities and angle of attack values, particle image velocimetry (PIV) experiments are performed. Laser plane is placed perpendicular to the free stream velocity at the downstream of the wing in order to analyze the wing tip vortices. The wing tip vortices of the four half wing models are recorded at two different downstream locations from the wing tip. Vector maps, velocity magnitude, vorticity, turbulence kinetic energy, Reynolds stress component and vortex core radii are analyzed. The aim of this study is to validate the numerical results in a separate study with load cell and PIV measurements of a morphing wing. By this approach it is shown that, for level flight, the three morphing wing shapes are optimized from the base wing properly for the particular velocities they are designed for.