• Transonic Buffet
• Unsteady Aerodynamics

This thesis presents an experimental study of the transonic buffet on a three dimensional unswept wing. The main goal is to assess possible effects on buffet due to cross-flow velocity field and Aspect Ratio variations. The first part of the thesis aims to provide the reader with a deep understanding of the buffet phenomenon, followed by a short overview on aerodynamic fences which represents a necessary component to simulate different aspect ratios. The experiments have been conducted at TU Delft Aerospace Faculty consisting of three main experimental campaigns, each of them having a specific goal. The first one aims to identify the aerodynamic conditions under which the buffet is fully developed, the second one to evaluate buffet at different aspect ratios and the third one to identify the velocity field development for some of the configuration analyzed in the second campaign. BOS technique has been used for the first two campaigns and PIV for the last one. The thesis will show by spectral analysis and the characterization of the shock wave position that the cross flow velocity field is actually influencing the buffet resulting in a clear displacement of the shock wave average position towards the trailing edge and enhancing the shock wave oscillation range. Similar considerations will be presented for the various aspect ratios analyzed. In the last part of the thesis, few guidelines for future research will be provided.