Abstract
An aeroelastic model based on a two-dimensional unsteady vortex-lattice method is used to study the dynamic behavior of elastically supported flat plates interacting with an incompressible uniform flow near the ground. The ground effect is simulated by the image technique. The air and the plate together are treated as a single dynamic system, and all of the equations of motion are integrated simultaneously and interactively in the time domain by means of an iterative scheme based on predictor corrector techniques. The present results show that the plates are destabilized by the proximity to the ground: the lower the height, the lower the airspeed at the onset of flutter. No structural damping was included in the present model, but damping is expected to raise the critical airspeed. The complete aeroelastic model is general and versatile; the aerodynamic model is inherently nonlinear and the structural model may be either linear or nonlinear. As the amplitude of the flutter motion grows, the nonlinear aerodynamic model caps the motion, which results in a limit cycle. Moreover, the extension to three dimensions is straightforward.