Hypersonic Fluid–Thermal–Structural Interaction of Cone–Slice–Ramp: Computations with Experimental Validation

The paper presents an investigation of fluid–thermal–structural interaction (FTSI) on a complex geometry in hypersonic flows. The objective is to assess high-fidelity numerical tools for FTSI by validating two numerical frameworks against wind-tunnel data. We choose a cone–slice–ramp geometry with a wedge angle of 30 deg subjected to a laminar inflow at Mach 8. First, the time-averaged and the time-resolved laminar flow solutions are validated and highlight the mean flow features and their unsteady characteristics, including low-frequency bubble breathing and shear-layer flapping at a higher frequency. The numerical analysis reveals the presence of upstream and downstream legs of streamwise vortices. Next, FTSI analysis is performed at a tractable computational cost by decomposing the numerical frameworks into a quasi-steady FTSI (QS-FTSI) analysis and a transient fluid–structure interaction (FSI) analysis based on the disparity of the characteristic timescales. The QS-FTSI results highlight the shear-layer reattachment as the dominant source heating the structure, with nonuniform spanwise variations due to the streamwise vortices. The temperature increase drives the decrease in the structural modal frequencies. The FSI analysis was performed for an unheated, undeformed structure and a nominal heated and deformed structure. The average error in the predicted FSI frequency of the unheated panel is 2.65% in comparison to the experimental data; however, this value increases to 7.42% for the heated panel. The frequency peaks are associated with the structural mode shapes via dynamic mode decomposition analysis and show a close resemblance to natural modes, indicating weak FSI coupling. The FTSI study concludes that for a cone–slice–ramp configuration under the present inflow conditions, the interaction mostly occurs in a one-way coupled manner, where the flowfield drives the thermal and structural response of the panel.