An Experimental and Computational Correlation Study for Fluid-Thermal-Structural Interaction of a Control Surface in Hypersonic Flow

Abstract

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 from PSU and USAFA against wind-tunnel data. We choose a cone-slice-ramp (CSR) geometry with a wedge angle of 30 degrees subjected to a low Reynolds number inflow at Mach 8. The computational costs are kept tractable by decomposing the numerical frameworks into a quasi-steady FTSI (QS-FTSI) analysis and a transient fluid-structure interaction (FSI) analysis based on the assessment of the characteristic time scales. The time-resolved and the time-averaged solutions obtained from the laminar fluid solvers are validated to assess the modeling accuracy of the mean flow features and their unsteady characteristics. The predictions show all the major flow features generated on the CSR with low-frequency oscillation and the shear layer flapping at a higher frequency. The numerical effort observes the presence of upstream and downstream legs of streamwise vortices that cannot be easily observed in the experiment. The QS-FTSI results highlight the streamwise vortices as the dominant source heating the structure. The effect of this temperature increase results in a decrease in the structural modal frequencies. Then, the FSI was analyzed for an unheated, undeformed structure. The predicted spectral content using the numerical accelerometer is compared to the experimental data where the first three peaks are distinguishable and match well. These peaks are associated with their corresponding mode shapes of the structure by dynamic mode decomposition. The FTSI study concludes that for a cone-slice-ramp with a 1mm thick panel under the present inflow conditions, the streamwise vortices post reattachment act as the dominant heating source. The temperature rise modifies the modal content of the structure. The effect of structural displacement during prolonged heating or oscillation during fluid-structure interaction is minimal on the flow field. Finally, based on the findings, recommendations are made for improving the computational frameworks.