Validation Experiment for Shock Boundary Layer Interactions: Sensitivity to Upstream Geometric Perturbations

Abstract

The sensitivity of two shock boundary layer interactions (SBLIs) { a compression corner interaction and an incident shock interaction { to small geometric perturbations (h < 0:2 0) was investigated using particle image velocimetry (PIV) measurements. Tests were performed in a continuously operated Mach 2.1 wind tunnel with a low aspect ratio test section. The primary oblique shock was generated by a 1.1mm high 20 degree compression wedge on the top wall of the tunnel, and small bumps were introduced upstream on the opposite wall. A total of 100 perturbed cases were tested; 45 for the compression corner interaction and 55 for the incident shock interaction. This dataset is well suited to be used for the validation of CFD codes which are intended to be used in design and analysis of systems with stochastic inputs. Both the compression corner and incident shock interactions were very sensitive to perturbations in a given region (-69mm < xp < -54mm), and insensitive to perturbations outside of it. Depending upon the location of the perturbations, the compression corner interaction could be strengthened or weakened signicantly. Areas of high wall-normal velocity in the incident SBLI were intensied as larger perturbations were added in the sensitive region. For all perturbations, the incident shock interaction either moved upstream or stayed in the same location. The deviation in the position of this SBLI from its unperturbed location was a strong function of both the location and size of the perturbations.