We study both experimentally and numerically the aeroelastic response of a pre-stressed curved aileron in a high Reynolds number flow undisturbed at infinity. The structure is designed to have a peculiar nonlinear behavior. Specifically, the aileron has only one stable equilibrium when the external forces are vanishing, but it is bistable when distributed aerodynamic loads are applied. Hence, for sufficiently high fluid velocities, another equilibrium branch is possible. We test a prototype of such an aileron in a wind tunnel. A sudden change (snap) of the shell configuration is observed when the fluid velocity exceeds a critical threshold: the snapped configuration is characterized by sensibly lower drag. However, when the velocity is reduced to zero, the structure recovers its initial shape. A similar 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.

我们通过实验和数值研究了无限远不受干扰的高雷诺数流中预应力弯曲副翼的气动弹性响应。该结构被设计成具有特殊的非线性行为。具体来说，当外力消失时，副翼只有一种稳定平衡，但当施加分布式气动载荷时，副翼是双稳态的。因此，对于足够高的流体速度，另一个平衡分支是可能的。我们在风洞中测试了这种副翼的原型。当流体速度超过临界阈值时，会观察到壳构型的突然变化（折断）：折断的构型的特点是阻力明显较低。然而，当速度降至零时，结构恢复其初始形状。类似的非线性行为对于减阻策略具有重要的应用，因为类钝体和类细长体行为之间的过渡由自由流流体速度控制，并且不需要任何外部驱动。