Fluid-Structure Interactions of a Hemispherically Rounded Blunt Fin over a Compliant Panel in Mach 2 Flow

The fluid-structure interactions of a blunt fin mounted over a compliant panel in Mach 2flow were investigated. The test geometry consisted of a thin, flexible panel fixed on all edges with a blunt fin with a hemispherically rounded leading edge mounted in a manner that the leading edge of the fin overhung the panel. The blunt fin was also pivoted to several angles of attack to the oncoming flow. This allowed for the study of the dynamic system created by the interactions between the flexible panel and the blunt fin geometries. Both rigid and compliant panel models were also used in order to provide a comparison between the flow with and without the dynamics of the compliant panel. High-speed schlieren and oil flow visualizations showed that the time-averaged flow remained almost entirely unchanged between the rigid and compliant panels. The instantaneous flow fields, however, showed a highly dynamic system where the compliant panel induced oscillatory shock waves that were both stationary and freely moving. Simultaneous high-speed schlieren visualization and stereo digital-image correlation showed a strong linkage between the motion of the shock waves and the deformation of the panel. This was demonstrated through frequency analysis and modal decomposition of the panel deformation and shock motions.