Flow Field Estimation of Supersonic Open Cavity Flows Conditioned on Time-Resolved Pressure Measurements*

Open cavity flows are dynamically complex flows which are further complicated by aero-acoustic resonance phenomena.  The complex phenomena in the flow are driven by the dynamics of the shear layer at the cavity opening and how it interacts with the downstream wall.  To better understand the complex nature of the flow, it is essential to comprehend the flow in a simplified and reduced manner. To this end, experiments were conducted in a supersonic wind tunnel flow facility operating at Mach 1.4 for an open cavity of L/D = 6. The measurements comprised of particle image velocimetry with synchronous time-resolved pressure measurements at multiple points on the cavity floor and aft wall. Stochastic estimation and other flow estimation techniques in conjunction with proper orthogonal decomposition were applied to the measurements to estimate the spatio-temporal modes of the velocity field conditioned on the pressure measurements. Decomposition in this manner helped better analyze Rossiter modes that dominate the scales and dynamics of the flow at specific frequencies.  Furthermore, the temporal estimation of the cavity shear layer demonstrates the complex fluid interactions with the cavity aft wall.