Flow-induced vibrations of high mass ratio flexible filaments freely hanging in a flow

The behavior of high mass ratio flexible filaments freely hanging in steady horizontal uniform flows is experimentally and theoretically investigated. When the flow velocity is small, static equilibrium states, where the filaments are inclined to the flow, are observed. Then, above a critical value of the wind velocity, the filaments exhibit periodic oscillations in the vertical plane. The problem is theoretically addressed considering the beam theory equations for the filament dynamics where the action of the flowing fluid is modeled using semiempirical expressions. These equations are first solved for the stationary equilibrium states. Then, the stability of these steady solutions relative to small perturbations is analyzed. A good agreement between experimental and theoretical results is found. (C) 2005 American Institute of Physics.