Experimental study of fluid-thermal-structural interactions in a Mach-10 compression corner using super-ellipse-based photogrammetry

Abstract An experimental study is conducted of the fluid-thermal-structural interaction of a clamped compliant panel exposed to the intense shock-wave/boundary-layer interaction (SWBLI) induced by a compression ramp at Mach 10. Initial measurements of the underlying flowfield with a rigid ramp showed the incoming boundary layer to be transitional, and the SWBLI was observed to vary from attached to fully separated as the ramp angle was increased from 10 $$^\circ $$ ∘ to 30 $$^\circ $$ ∘ . For the compliant panel, a sealed cavity behind the panel allowed the effects of pressure-differential induced strains to be studied in the context of characterizing surface response to the aero-thermal load. Full-field, time-resolved panel deformations were measured using high-speed photogrammetry enabled by a new high-fidelity marker-tracking routine, which was shown to outperform existing methods. Substantial static panel deformations (of the order of several times the panel thickness) were produced by the intense aero-thermal loading environment. These deformations, combined with induced thermal and pressure gradients across the panel, were found to significantly modify the nature of existing panel modes (both the frequency and the displacement distributions) and introduce new, irregular mode shapes not predicted by classical clamped-plate theory; SolidWorks ® simulations were performed to demonstrate that these new mode shapes were a result of the underlying panel curvature. Increasing the ramp angle resulted in a wider variety of panel modes becoming excited, while increasing the pressure differential across the panel typically produced further increases in modal frequencies and decreases in vibrational amplitudes. The transient panel response was characterized and it was found that the lower frequency mode shapes tended to gradually increase in vibrational frequency as the panel heated up and further deformed; however, higher frequency modes ( $$f \gtrsim 3 \hspace{.075 cm} \textrm{kHz}$$ f ≳ 3 kHz ) generally showed the opposite behavior. Furthermore, as the panel deformed through the test time, the average vibrational spectra root-mean-square power was generally found to monotonically decrease.