Nonlinear aeroelastic response of panels
We consider the nonlinear aeroelastic response of panels supported by an elastic foundation in subsonic and supersonic flows. Previous studies of the nonlinear behavior of panels have revealed that they are capable of a variety of bifurcations, limit cycles and even chaotic responses. Thus, the fluttering panel provides a special opportunity to study the dynamics of a spatially and temporally complex system both analytically and experimentally. This paper focuses on new theoretical developments. A two-dimensional, simply supported panel with an elastic foundation in subsonic flow is studied using a linear stability analysis (including postbuckled behavior) and numerical integrations of the full non-linear equations of motion. It is shown that a panel in incompressible, subsonic flow can oscillate aperiodically. However, when structural damping is included in the model, the response diverges rather than flutters and becomes statically and dynamically stable in a buckled shape at all higher flow velocities. The results of numerical studies of a panel in supersonic flow are also presented including a fractal dimension estimate of the chaotic attractor. As is well known, only flutter occurs at high Mach numbers and sufficiently large dynamics pressures. This flutter, however, can be periodic or chaotic. The dimension of the spatiotemporal chaos for this aeroelastic system is shown to be low (<3).
