A wing glove for active flow control free-flight experiments using a one-fifth dynamically scaled Aeromot 200S Super Ximango motor glider was developed. The wing glove has a modified NACA 643 − 618 airfoil and is instrumented with off-the-shelf pressure transducers and amplitude-modulated synthetic jet actuators. Before the flight-testing was commenced the wing glove and the instrumentation were tested in two open return low-speed wind tunnels. Due to the low-aspect ratio of the glove, particular attention was paid to the two-dimensionality of the flow field over the wing glove. Several flight experiments were carried out and free-flight data with and without actuation were recorded. Unexpected challenges that were encountered during the flight-testing are discussed and an analysis of the wall pressure data in the frequency domain is provided.

The mean flow topology for flows with three-dimensional separation can be highly complex and the unsteady fluid dynamics are largely unexplored. Water tunnel experiments and direct numerical simulations were carried out to obtain insight into the threedimensional separation topology for submarine-like geometries. Particle image velocimetry was employed for obtaining quantitative mean flow data. A hemisphere-cylinder model and a model of the Virginia Tech "ellipsoid" geometry were developed for investigating threedimensional separation. At 10 degrees angle of attack, a large laminar separation bubble developed on the nose of the hemisphere-cylinder model. The bubble was shedding intermittently. When the angle of attack was increased to 30 degrees two leeward vortices were generated and the bubble shedding was reduced. The "ellipsoid" model did not exhibit a laminar nose separation bubble at angle of attack. However, for combined roll and yaw angles or, alternatively, angle-of-attack/side-slip angle combinations highly asymmetric configurations of the leeward vortices were obtained. This asymmetry may explain the static roll-instability observed in earlier experiments at Virginia Tech for mixed roll/yaw maneuvers.

A two-dimensional laminar separation bubble on a flat plate is studied experimentally using Particle Image Velocimetry (PIV) and flow visualization. The separation bubble was generated on a flat plate by an imposed adverse pressure gradient. The adverse pressure gradient was generated by using an inverted wing with a NACA 643-618 airfoil mounted above the flat plate. A parametric study of the effect of the upstream flow velocity and the induced pressure gradient on the mean flow topology and the unsteady behaviour of the separation bubble was carried out in the low-speed water tunnel of the Hydrodynamics Laboratory at the University of Arizona. The structure and dynamics of the laminar separation bubble were found to depend strongly on the aforementioned parameters. As the flow velocity is reduced, at very low flow velocities the bubble is seen to undergo a drastic change in geometry, resulting in bubble bursting. An attempt is made in this work at understanding the physics of bubble bursting. For certain flow conditions, strong vortex shedding near the reattachment region of the bubble was observed, which is a characteristic behaviour of short bubbles. High-resolution spatio-temporal PIV measurements were made to analyze the formation and breakdown of these flow structures.