Experimental studies of transonic buffet
Anne-Marie Schreyer
Abstract: For modern passenger aircraft, the flow around the wings becomes transonic. Under certain combinations of Mach number and angle of attack, the phenomenon of transonic buffet can occur. In this highly unsteady flow field, a local shock wave oscillates on the suction side of the wing, inducing flow separation and strongly varying flow conditions. These effects are detrimental for the aerodynamic performance and may, furthermore, induce potentially harmful structural vibrations. The occurrence of the phenomenon thus must be avoided – which strongly limits the flight envelope. To overcome these issues and lay the foundations for future flow-control approaches, a deeper understanding of the buffet instability is crucial.
In this contribution, our ongoing research efforts on transonic buffet, its potential influence on the aerodynamics of the aircraft’s tailplane (which is impacted by the wake of the main airfoil or wing), as well as differences between the phenomenon on 2D airfoils and 3D wings, will be presented. We use multiple experimental methods and modal analysis approaches to analyze these flows. Amongst other aspects, the talk will focus on our use of postprocessing methods to extract quantitative information from flow visualizations.
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