Three-dimensional Aeroelastic and Aerothermoelastic Behavior in Hypersonic Flow

Abstract

The aeroelastic and aerothermoelastic behavior of three-dimensional configurations in hypersonic flow regime are studied. The aeroelastic behavior of a low aspect ratio wing, representative of a fin or control surface on a generic hypersonic vehicle, is examined using third order piston theory, Euler and Navier-Stokes aerodynamics. The sensitivity of the aeroelastic behavior generated using Euler and Navier-Stokes aerodynamics to parameters governing temporal accuracy is also examined. Also, a refined aerothermoelastic model, which incorporates the heat transfer between the fluid and structure using CFD generated aerodynamic heating, is used to examine the aerothermoelastic behavior of the low aspect ratio wing in the hypersonic regime. Finally, the hypersonic aeroelastic behavior of a generic hypersonic vehicle with a lifting-body type fuselage and canted fins is studied using piston theory and Euler aerodynamics for the range of 2.5 ≤ M ≤ 28, at altitudes ranging from 10,000 feet to 80,000 feet. This analysis includes a study on optimal mesh selection for use with Euler aerodynamics. In addition to the aeroelastic and aerothermoelastic results presented, three time domain flutter identification techniques are compared, namely the moving block approach, the least squares curve fitting method, and a system identification technique using an Auto-Regressive model of the aeroelastic system. In general, the three methods agree well. The system identification technique, however, provided quick damping and frequency estimations with minimal response record length, and therefore offers significant reductions in computational cost. In the present case, the computational cost was reduced by 75%. The aeroelastic and aerothermoelastic results presented illustrate the applicability of the CFL3D code for the hypersonic flight regime.

Aeroelastic and Aerothermoelastic Behavior in Hypersonic Flow

“…In practice, control surfaces on hypersonic vehicles will be required to have a small angle of attack to produce the necessary control forces. It has been shown [80,81] that for the unheated case, a small angle of attack will not significantly modify the flutter boundary of a two-dimensional typical section. However, angle of attack is important when aerodynamic heating is considered, because it introduces asymmetry in the temperature distribution between the upper and lower surfaces of a wing.…”

Response of skin panels to combined self- and boundary layer-induced fluctuating pressure

“…Historically, the structural behavior to these different sources has been considered separately. In the first class of problems, the quasi-static panel response (Kontinos, 1997;Culler et al, 2009), and dynamic instabilities (McNamara et al, 2005;Mei et al, 1999;Culler et al, 2009) has been studied by modeling the boundary layer loads and other external acoustic excitations: (1) as a random in time, and uniform in space acoustic load (Przekop and Rizzi, 2006;Spottswood et al, 2010), (2) using semi-empirical models (Maestrello, 1969;Hwang et al, 2009;Hambric et al, 2004;Coe and Chyu, 1972;Wu and Maestrello, 1995), and (3) using high-fidelity Computational Fluid Dynamics (CFD) simulations (Frendi, 1997(Frendi, , 2004. There are limitations of each of these approaches.…”

Transient Temperature Effects on the Aerothermoelastic Response of a Simple Wing

“…The inclusion of heating was found to significantly change the aeroelastic response of the wing, as it resulted in flutter in conditions that were aeroelastically stable for the cold wing. A number of steady aerodynamic models have been coupled with the structural dynamics, namely piston theory, Euler and Navier-Stokes aerodynamics [16,23,24]. These studies have verified the use of third order piston theory as an accurate model of the aerodynamics in hypersonic flight.…”

“…Whereas the early research was instrumental in providing the basis for the aerothermoelastic design of the X-15 and the space shuttle [3][4][5], the current focus is on the development of hypersonic technologies for next-generation reusable launch vehicles and hypersonic cruise vehicles [6][7][8]. Current research includes: development of reduced order models for aerothermoelastic systems [9,10], structural optimisation [11], uncertainty propagation [12,13], coupling CFD with aerothermoelastic models [14], two-dimensional nonlinear flutter models [15] and three-dimensional flutter models [16]. This work has shown that the dynamic behaviour of the structure under the harsh thermal environment must be investigated for hypersonic aircraft to become a reality.…”