High-Speed PIV of shock boundary layer interactions in the transonic buffet flow of a compressor cascade

Abstract The dynamics of a transonic buffet flow on the suction side highly loaded 2-D compressor blade model is investigated at chord-based Reynolds number $$1.4 \times 10^6$$ 1.4×106 and an inlet Mach 1.05. Near stall detached bow shock exhibits pronounced modal oscillations frequencies $${\omega ^*}=2\pi f c / U_1=2.27$$ xmlns:mml="http://www.w3.org/1998/Math/MathML">??=2?fc/U1=2.27 which are not related to any structural aeroelastic modes. High-speed PIV several stations along chord provides chordwise velocity spectra wave propagation velocities shock-induced perturbations. For this purpose, double-pulse laser system with high-repetition rate was set up consisting two combined DPSS lasers. This enables time-resolved using frame straddling 100 kfps pulse separations down 800 ns. Synchronized high-speed shadowgraph imaging simultaneously locates position shock. Based cross-correlations between time records points position, perturbations determined upstream downstream from measured data indicate that feedback occurs region immediately foot plane shock, transverse disturbances convected. observation contrary Lee’s Lee (AIAA J 28(5):942–944, 1990) describes self-sustained shock-buffet as consequence shock–trailing edge interactions. Graphic