On the Control of Instabilities in Fluid-Structure Interaction Problems

Abstract

Energy dissipation due to sloshing liquid in torus-shaped nutation dampers is studied using the simple potential flow procedure in conjunction with the first order boundary layer correction. This is followed by an extensive test program to assess effectiveness of the dampers in arresting relatively low frequency oscillations frequently encountered in industrial aerodynamics problems. results suggest damping characteristics to be particularly sensitive to physical properties of the liquid used, its height in the torus, damper geometry, and dynamical parameters representing amplitude and frequency. Tests on two and three dimensional structural models in smooth flow and boundary layer wind tunnels, with the models undergoing vortex-induced resonance and galloping instability, suggest that nutation dampers can effectively suppress both forms of instabilities over a wide range of wind speed. The concept is likely to prove effective in tackling industrial aerodynamics, earthquake and ocean engineering problems