Affiliation:
1. RWTH Aachen University, 52062 Aachen, Germany
Abstract
The present experimental investigation characterizes the development and decay of transonic buffet on the supercritical airfoil OAT15A, as well as the flow field and shock motion throughout the fully developed buffet cycle. A comprehensive database of high-speed focusing schlieren sequences provides access to the temporal and spectral behavior of the oscillatory shock motion within a broad parameter space, covering Mach numbers 0.68–0.80 and angles of attack 3.3–6.5 deg. From these data, multiple temporal and spectral properties characterizing the distinctness of the shock oscillation are extracted. Combining these indicators enables us to clearly distinguish fully established buffet from pre-buffet, buffet onset, and buffet offset. This criterion helps to interpret the diverse findings in the relevant literature cases. Particle-image velocimetry measurements provide detailed insight into the turbulence structure and behavior throughout a fully established buffet cycle at a Mach number of 0.72 and an angle of attack of 5 deg. Instantaneous and phase-averaged velocity maps indicate massive flow separation for shock positions close to the upstream limit. Velocity profiles illustrate the large intermittent velocity deficit persisting until the trailing edge and corroborate most pronounced separation when induced by an upstream-traveling shock wave. Representative phases of the buffet cycle visualize and quantify the severe modification of the flow topology modulated by the shock and lay the groundwork to improve the understanding of mechanisms governing shock buffet.
Funder
Deutsche Forschungsgemeinschaft
Publisher
American Institute of Aeronautics and Astronautics (AIAA)
Reference44 articles.
1. McDevittJ. B.OkunoA. F. “Static and Dynamic Pressure Measurements on a NACA 0012 Airfoil in the Ames High Reynolds Number Facility,” NASA TP-2485, 1985.
2. Transonic Flow about a Thick Circular-Arc Airfoil
3. Experimental Study of Shock Oscillation over a Transonic Supercritical Profile
4. Reynolds-Averaged Navier-Stokes Study of the Shock-Buffet Instability Mechanism
5. PearceyH. H. “Some Effects of Shock-Induced Separation of Turbulent Boundary Layers in Transonic Flow Past Aerofoils,” Aeronautical Research Council R&M 3108, 1955.
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