Control of a separating turbulent boundary layer using pulsed jets

This thesis investigates the control of a separating turbulent boundary layer using periodic excitation via pulsed jets. Experiments were conducted on an airfoil-like model subjected to an adverse pressure gradient at its curved trailing edge. Two different jet array configurations - streamwise and skewed slits - were compared to assess their effectiveness in modifying the flow. Detailed characterization of the actuation system was performed using hot wire anemometry, and the interaction between the pulsed jets and the boundary layer was studied through static surface pressure measurements and particle image velocimetry. Results indicate that skewed slits enhance the coherence of the generated vortical structures, leading to more effective separation control compared to streamwise slits. The study also highlights the critical influence of actuation frequency, velocity ratio, and jet orientation on the separation dynamics; moreover, it was found that the flow field - when subjected to actuation - shows a much higher degree of variability in the spanwise direction than anticipated. The findings contribute to a deeper understanding of active flow control strategies for drag reduction and improved aerodynamic performance in practical applications.