Instability of Axial Flow Over a Plate Hinged at Its Leading Edge

This paper describes a study of the flow instability over a plate hinged at its leading edge by the pseudospectral numerical method for fluid loading and the Galerkin method for the eigen-value problem. The mechanism of modal coupling for the plate flutter is illustrated. It is found that flutter arises from the coupling between the first and second in-vacuo modes, with flow-to-structure energy transfer. The fluid loading on the second in-vacuo mode is found to be the dominant source of instability. Compared with a cantilever plate with the same material property, the plate with a simply supported leading edge has similar threshold of flutter velocity, which suggests that the bending stiffness of the plate is crucial for the stability instead of the structural boundary condition at the leading edge. This conclusion is also validated by the analytical study for a simplified model in which the flexible plate is replaced by two rigid plates connected by a hinge.