Shock-induced Buffet

Dynamics and interaction of shock oscillation and flow separation in transonic profile flow

Shock-induced buffet represents a flow instability that causes strong, periodic pressure fluctuations and structural oscillations on components exposed to transonic flow. These effects can significantly limit the operational envelope of modern aircraft configurations. Reliable prediction of the conditions under which buffet and the associated aeroelastic interactions occur is therefore essential for safe and efficient aircraft design. In this research project, the transonic flow around various airfoils is investigated experimentally to gain a fundamental understanding of the physical origin and dynamics of this instability. Experiments are conducted in the Trisonic Wind Tunnel Munich (TWM) using advanced optical flow measurement techniques capable of capturing density variations, surface pressure, and velocity fields with high temporal resolution. This approach allows for a systematic study of the relationship between boundary-layer behavior (especially flow separation) and shock motion. Furthermore, the propagation speed of acoustic waves and the convection velocity of coherent structures in the separated flow are determined to validate and refine existing buffet-frequency prediction models. Variations in Mach number and angle of attack support the development of physically based models for buffet onset and dynamics. By combining refined measurement methods and precise data analysis, the project is expected to make a significant contribution to understanding the mechanisms underlying transonic buffet and its influence on oscillation frequency and amplitude.

Project Leader: Dr. Sven Scharnowski

Project Researcher: Dr. Eric Ibarra

Funding Organization: German Research Foundation (Deutsche Forschungsgemeinschaft (DFG))

Gepris: https://gepris.dfg.de/gepris/projekt/535550047

Publications:

  • Ibarra, Eric, Kähler, Christian J., Scharnowski, Sven (2025) Characterization of focusing schlieren system.21st International Symposium on Flow Visualization, Tokyo, Japan, 21–25 June