5 research outputs found
Study of Unsteadiness due to 3-D Shock-Boundary Layer Interaction in Flow over a Square-faced Protuberance
The dynamics of shock-induced unsteady separated flow past a
three-dimensional square-faced protuberance is investigated through wind tunnel
experiments. Time-resolved schlieren imaging and unsteady surface pressure
measurements are the diagnostics employed. Dynamic Mode Decomposition (DMD) of
schlieren snapshots, and analysis of spectrum and correlations in pressure data
are used to characterize and resolve the flow physics. The mean shock foot in
the centreline is found to exhibit a Strouhal number of around 0.01, which is
also the order of magnitude of the Strouhal numbers reported in the literature
for two-dimensional shock-boundary layer interactions. The wall pressure
spectra, in general, shift towards lower frequencies as we move away from
(spanwise) centreline with some variation in the nature of peaks. The
cross-correlation analysis depicts the strong dependence of the mean shock
oscillations to the plateau region, and disturbances are found to travel
upstream from inside the separation bubble. Good coherence is observed between
the spanwise mean shock foot locations till a strouhal number of about 0.015
indicating that the 3-D shock foot largely moves to-and-fro in a coherent
fashion.Comment: 16 pages, 21 figure