By-pass transition to airfoil flutter by transient growth due to gust impulse

M. Schwartz (1) , S. Manzoor (1) , Pascal Hémon (1) , Emmanuel de Langre (1)

1 LadHyX - Laboratoire d'hydrodynamique

We present an experimental study which shows that the mechanism known as transient growth of energy, can cause flutter instability of a nonlinearly flexible airfoil at a wind velocity below the linear critical flutter velocity. A flap mounted upstream a flexible airfoil in a wind tunnel generates a single gust which triggers the plunge and pitch oscillations. This gust is characterized using two-component hot-wire anemometry. For the first time experimental evidence is provided to confirm the theoretical scenario of a by-pass transition to flutter by transient growth. From an engineering point of view, transient growth might explain also the premature structural fatigue encountered in structures subject to wind. © 2009 Elsevier Ltd. All rights reserved.

Domains: Fluid mechanics [physics.class-ph]; Fluids mechanics [physics.class-ph]

M. Schwartz, S. Manzoor, Pascal Hémon, Emmanuel de Langre. By-pass transition to airfoil flutter by transient growth due to gust impulse. Journal of Fluids and Structures, 2009, 25 (8), pp.1272-1281. ⟨10.1016/j.jfluidstructs.2009.08.001⟩. ⟨hal-01021128⟩