PSP Investigation of a Hemispherically Rounded Blunt Fin over a Compliant Panel in Supersonic Flow

The fluid-structure interactions of a hemispherically rounded fin mounted over a compliant panel in Mach 2 flow were investigated as a continuation to a previous study which investigated the same fluid-structure interaction case. The main focus of this study was to investigate the pressure distribution across the surface of the fin using pressure-sensitive paint (PSP). The test geometry for this study consisted of a thin, flexible panel fixed on all edges. A fin with a hemispherically rounded leading edge was mounted in a manner that the leading edge of the fin overhung the panel. The fin was also deflected to several angles of attack with respect to the oncoming flow. Both a rigid and a compliant panel model were used in order to provide a comparison between the flow with and without the dynamics of the compliant panel. The time-averaged pressure distributions for the rigid panel visualized the flow features on the fin that are inherent to the fluid-structure interaction, without the impact of the compliant panel. Evaluation of the aerodynamic loading on the fin showed that at low angles of attack for the compliant panel, the fin experienced higher loading compared to the rigid panel. However, at high angles of attack, the aerodynamic load on the fin was found to be similar for both the rigid and compliant panels. Spectral analysis of the pressure distributions with the compliant panel revealed the oscillation of the flow structures on the surface of the fin. The frequencies of these oscillations agreed with the frequency content of the oscillations of the compliant panel found previously. Spectral proper orthogonal decomposition verified that the flow structures found in the time-averaged pressure distributions also exhibited the same frequency content.