Study of fluid–thermal–structural interaction in high-temperature high-speed flow using multi-fidelity multi-variate surrogates

This study investigates the impact of the high-temperature effect, especially the real gas effect and chemical reactions, on hypersonic aerothermodynamic solutions of double cone and double wedge configurations, as well as the fluid–thermal–structural interaction of a double wedge configuration in hypersonic flow. First, a high-temperature computational fluid dynamics (CFD) code was benchmarked and correlated with experimental results, emphasizing the impact of high-temperature effects as well as turbulence modeling on heat flux prediction. Subsequently, the multi-fidelity multi-variate Gaussian process regression (M²GPR ) method for problems with high-dimensional outputs was developed to create an aerothermal surrogate model. The model achieves a balance between model accuracy and computational cost of sample generation, using the combination of a few high-fidelity samples and many low-fidelity samples. The numerical examples show that, using the M²GPR formulation, the required number of high-fidelity samples may be reduced by over 80% while maintaining an accuracy comparable to the high-fidelity CFD solvers. In addition, a geodesic-distance-based metric is developed to inform the choice of high-dimensional datasets of different fidelities for the M²GPR surrogate with improved accuracy. Finally, the aerothermal surrogate was applied to study the impact of the high-temperature effect on the aerothermoelastic response of a hypersonic skin panel, emphasizing the necessity of the accurate characterization of the localized heat flux for reasonable assessment of the response of a compliant structure in high-speed high-temperature flowfield.