Coupled Thermal Model for Nonlinear Panel Flutter

A nonlinear formulation is developed that accounts for high-Mach-number, viscous flow over the external surface of an isotropic elastic panel. The formulation is unique in that the panel compressive stress is calculated as a result of fluid/structure thermal coupling. Two distinct heat transfer mechanisms are investigated. One is due to fluid viscosity, and the second is due to local flow over the panel. Here, in contrast with classical panel flutter studies, the in-plane load and dynamic pressure parameters are not wholly independent parameters. The equation of motion is based on von Karman large deflection plate theory and includes a geometric nonlinearity. Using Galerkin's s method, the resulting system of equations is solved by direct numerical integration. However, the parameter space representing the in-plane load is extensive, and therefore, numerical integration alone is not a feasible analysis method. As a supplement, the system of equations is analysed with a pseudoarclength continuation method. In this way, a new periodic regime is uncovered. However, the attractor becomes unstable as a result of additional heating. The results indicate that aerodynamic heating is the dominant heat transfer mechanism. For the conditions studied, the dynamic system is dominated by a stable fixed-point attractor. The aerothermoelastic panel flutter model formulated here is qualitatively similar to the classical model when the in-plane load is due to aerodynamic heating effects only.