Experiments in Fluids

, Volume 52, Issue 3, pp 591–604

Time-resolved stereo PIV measurements of shock–boundary layer interaction on a supercritical airfoil

Research Article

DOI: 10.1007/s00348-011-1074-6

Cite this article as:
Hartmann, A., Klaas, M. & Schröder, W. Exp Fluids (2012) 52: 591. doi:10.1007/s00348-011-1074-6

Abstract

Time-resolved stereo particle-image velocimetry (TR-SPIV) and unsteady pressure measurements are used to analyze the unsteady flow over a supercritical DRA-2303 airfoil in transonic flow. The dynamic shock wave–boundary layer interaction is one of the most essential features of this unsteady flow causing a distinct oscillation of the flow field. Results from wind-tunnel experiments with a variation of the freestream Mach number at Reynolds numbers ranging from 2.55 to 2.79 × 106 are analyzed regarding the origin and nature of the unsteady shock–boundary layer interaction. Therefore, the TR-SPIV results are analyzed for three buffet flows. One flow exhibits a sinusoidal streamwise oscillation of the shock wave only due to an acoustic feedback loop formed by the shock wave and the trailing-edge noise. The other two buffet flows have been intentionally influenced by an artificial acoustic source installed downstream of the test section to investigate the behavior of the interaction to upstream-propagating disturbances generated by a defined source of noise. The results show that such upstream-propagating disturbances could be identified to be responsible for the upstream displacement of the shock wave and that the feedback loop is formed by a pulsating separation of the boundary layer dependent on the shock position and the sound pressure level at the shock position. Thereby, the pulsation of the separation could be determined to be a reaction to the shock motion and not vice versa.

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Axel Hartmann
    • 1
  • Michael Klaas
    • 1
  • Wolfgang Schröder
    • 1
  1. 1.Institute of AerodynamicsRWTH Aachen UniversityAachenGermany