Investigating Fluid-Thermal-Structure Interactions of Hypersonic Control Fins

Hypersonic vehicles require control fins that can tolerate extreme aerothermal loads for guidance and stability. The fluid-thermal-structure interactions (FTSI) that occur over these control fins must be investigated using existing reduced order models (ROMs), as higher fidelity unsteady fluid models are too computationally expensive for use in engineering and design. ROMs that fall within the family of piston theory are investigated to determine their behavior over a range of parameters. The piston theory variants that are tested include local inviscid and viscous piston theory, as well as linear and nonlinear variants. These models are compared to unsteady two-dimensional Navier-Stokes Computational Fluid Dynamics (CFD). These tests are carried out on a panel oscillating according to a forced deformation on the downstream portion of a representative Mach 6 fin geometry. It is observed that viscous piston theory variants perform better than inviscid variants, that nonlinear effects are not significant, that higher panel mode number tend to perform worse, and that the impact of increasing the reduced frequency depends on the Reynolds number.