An elastic rotative nonlinear vibration absorber (ERNVA) as a passive suppressor for vortex-induced vibrations

Abstract

Vortex-induced vibration (VIV) is a self-excited and self-limited flow-induced vibration phenomenon of importance for both the academic and the technological communities. Particularly for the offshore engineering scenario, VIV plays an important role in the structural fatigue analysis. Hence, VIV suppression is a relevant topic. Among different solutions for VIV mitigation, this paper focuses on the numerical analysis of an elastic rotative nonlinear vibration absorber (ERNVA) as a device for passive suppression. The ERNVA consists of a mass placed at the tip of an axially elastic beam hinged to the cylinder by means of a linear dashpot. In this paper, the hydrodynamic loads are calculated using a wake-oscillator model, allowing comprehensive parametric studies for assessing the influence of the ERNVA parameters on its efficiency for the whole range of reduced velocities associated with the lock-in. Among other novel results, it is found that ERNVA can lead to a $$25\%$$ decrease in the maximum oscillation amplitude, being significantly more efficient than its counterpart characterized by a rigid rotating arm. Passive suppression is obtained not only for the peak, but within a certain range of reduced velocities. Curves showing the influence of the ERNVA parameters on the force coefficients for different values of reduced velocity are also innovative.