Aeroelastic instability of cantilevered flexible plates in uniform flow

TL;DR

This paper investigates the flutter instability of cantilevered flexible plates in uniform flow, highlighting the importance of three-dimensional effects and aspect ratio in predicting stability thresholds, and clarifying discrepancies with previous experiments.

Contribution

It provides a combined experimental and theoretical analysis of how aspect ratio influences flutter instability, emphasizing the role of three-dimensional effects.

Findings

Large aspect ratio plates exhibit hysteresis and 3D effects.

Two-dimensional models underestimate stability thresholds.

The nature of the bifurcation depends on flow and plate parameters.

Abstract

We address the flutter instability of a flexible plate immersed in an axial flow. This instability is similar to flag flutter and results from the competition between destabilising pressure forces and stabilising bending stiffness. In previous experimental studies, the plates have always appeared much more stable than the predictions of two-dimensional models. This discrepancy is discussed and clarified in this paper by examining experimentally and theoretically the effect of the plate aspect ratio on the instability threshold. We show that the two-dimensional limit cannot be achieved experimentally because hysteretical behaviour and three-dimensional effects appear for plates of large aspect ratio. The nature of the instability bifurcation (sub- or supercritical) is also discussed in the light of recent numerical results.