Delayed detached eddy simulation-based aerothermoelastic analysis of deployable control fin in supersonic and hypersonic flows

In the present work, nonlinear aerothermoelastic characteristics of a deployable control fin subjected to high supersonic and hypersonic flow are investigated. The delayed detached eddy simulation (DDES)-based computational fluid dynamics solver is strongly coupled to the finite element method-based structural dynamics and thermoelastic solver to perform coupled fluid-thermal-structural interaction analysis. A shear stress transport (SST) k - omega based DDES model is used for turbulence modeling, whereas the advection upstream splitting method scheme is used for flux calculation, and for dynamic meshing, a diffusion-based smoothing method is used. To solve the governing nonlinear structural dynamics equations of motion in the time domain, the Hilber-Hughes-Taylor (HHT)-alpha method is used with the Newton-Raphson linearization technique. Profile preserving and conservative mapping-based interfacing modules are used to couple the different solvers. For the validation of the methodology, two experimental test cases are considered, and the computations are in very good agreement with the experimental results. Furthermore, the effects of Mach number, angle of attack, and joint freeplay on the fin's structural and aerodynamic characteristics are investigated and presented. The results show a complex flow behavior over the fin including several separation and attachment zones because of the deployable joint arrangement. It is also observed that the temperature due to the severe aerodynamic heating effect is very high at the leading edge and increasing thickness zones at the joint. With increasing joint freeplay, the amplitude of the deformation response increases, indicating increased dynamic instability.