Hypersonic Aerothermoelasticity with Application to Reusable Launch Vehicles

The hypersonic aeroelastic and aerothermoelastic problem of a double-wedge airfoil typical cross-section is studied using three different unsteady aerodynamic loads: (1) third-order piston theory, (2) Euler aerodynamics, and (3) Navier-Stokes aerodynamics. Computational aeroelastic response results are used to obtain frequency and damping characteristics, and compared with those from piston theory solutions for a variety of flight conditions. Aeroelastic behavior is studied for 5 < M < 15 at altitudes of 40,000 and 70,000 feet. A parametric study of offsets, wedge angles, and static angle of attack is conducted. All the solutions are fairly close below the flutter boundary, and differences between the various models increase when the flutter boundary is approached. For this geometry, differences between viscous and inviscid aeroelastic behavior are not substantial. Results illustrate that aerodynamic heating reduces aeroelastic stability. In addition, the hypersonic aeroelastic problem of a 3-D low aspect ratio wing, representative of a fin or control surface present on hypersonic vehicles, is studied using 1st and 3rd order piston theory and Euler aerodynamics. Finally, application of this approach to a generic vehicle resembling a reusable launch vehicle is discussed. The results presented serve as a partial validation of the CFL3D code for the hypersonic flight regime.