Single-Camera Three-Dimensional Velocity Measurement of a Fin-Generated Shock-Wave/Boundary-Layer Interaction

Abstract

The three-dimensional (3-D) shock-wave/boundary-layer interaction (SBLI) between a fin-generated shock and a turbulent boundary layer is examined using plenoptic particle image velocimetry (PIV): a 3-D diagnostic technique that uses a single camera to obtain direct 3-D velocity measurements. A sharp, unswept fin at a 15 deg angle of attack in Mach 2 flow generates a 45 deg oblique shock that interacts with the boundary layer on the tunnel floor. This type of SBLI has been extensively studied in quasi-two-dimensional representations, but no work up to this point has been done to capture true 3-D measurements. This work represents the first 3-D velocity field measurements in supersonic flow using plenoptic PIV, as well as the first 3-D velocity measurements of a fin-generated SBLI. Flow features including the -shock structure and slip region expected from this SBLI were able to be resolved, and the 3-D imaging allowed for better visualization of the overall flow topology. Plenoptic PIV enabled the visualization of features not considered in previous literature, particularly the 3-D curvature of the inviscid shock and effects from an expansion region emanating from the fin tip due to the finite fin height. Plenoptic PIV results are compared with inviscid shock theory and stereoscopic PIV for validation purposes.