Velocity and surface pressure measurements in an open cavity

Subsonic flow of approximately Mach 0.2 over cavities with L/D ratios of 5.16 and 1.49 were studied experimentally using particle image velocimetry (PIV), surface pressure measurements, and hot-wire measurements. The incoming boundary layer was turbulent in both cases. The PIV data was analyzed to yield mean flow characteristics, vorticity field information, and two-point statistics for the velocity field. The hot-wire data was combined with surface pressure measurements to detail the correlations between velocity and pressure fluctuations. An analysis of the correlation between surface pressure measurements shows contrasting characteristics for the two cavity aspect ratios. The PIV data was combined with surface pressure measurements through the application of quadratic stochastic estimation to predict the time-dependent behavior of the velocity field. An examination of the results supports the existence of different cavity flow modes, as has been suggested in much of the literature.