Effect of realistic distributed loads on the bi-stable behavior of a pre-stressed aileron (Q6546224)

In this paper the aeroelastic response of a pre-stressed curved aileron in a high Reynolds number flow is studied both experimentally and numerically. The structure is designed to have a nonlinear behavior having one stable equilibrium when the external forces are vanishing, but another equilibrium branch is possible when distributed aerodynamic loads are applied. A prototype of such an aileron was tested in a wind tunnel, where a sudden change of the configuration is observed when the fluid velocity exceeds a critical threshold leading to a configuration characterized by sensibly lower drag. Such a nonlinear behavior can have important applications for drag-reduction strategies since the transition between a bluff body-like and a slender body-like behavior is controlled by the free-stream fluid velocity and does not require any external actuation.