Hypersonic panel flutter studies on curved panels

Abstract

The flutter of shallow, curved, heated three dimensional orthotropic panels exposed to hypersonic airflow is considered. The equations of motion, based on Marguerre shallow shell theory, are derived for two types of panel curvatures. The formulation also allows for the presence of a shock upstream of the panel and a general temperature distribution. The equations are solved using Galerkins method combined with direct numerical integration in time to compute stable limit cycle amplitudes. Nonsimple harmonic motions are observed for sufficiently high post-critical dynamic pressure values and the complex behavior is illustrated using representative phase plane plots. Aerodynamic healing, the presence of a shock in the flow, and nozero initial curvature are shown to significantly affect the aeroelastic behavior. A conlparison of the aerodynamic loads predicted by 3rd order piston theory, the Euler equations and the Navier Stokes equations suggests that the solution of the fully coupled aerothermoelastic problem may be necessary to fully understand the aeroelastic behavior of a panel in hypersonic flow.