Passive suppression of flow-induced vibrations of a cantilevered pipe discharging fluid using non-linear vibration absorbers

This paper addresses the problem of passive suppression of vibrations induced by flow in a cantilevered pipe discharging fluid. The suppressor utilized, called rotative non-linear vibration absorber (NVA, for short), is composed of a mass connected to the extremity of a rigid bar linked to the pipe by means of a hinge and a rotational damper. The NVA is defined by its mass, radius and damping coefficient. The suppressor may affect the pipe dynamics in two different ways, which are the inherent mass addition to the system, and the fact that the device can rotate and thus can dissipate energy through its damper. The former is characterized by its mass and position along the pipe while the latter is also a function of other design parameters, such as damping coefficient and radius. It is shown that while mass additions play an important role in the pipe stability, the energy dissipation associated with the relative motion between the device and the pipe is capable of alleviating the pipe vibrations. Considering a fixed set of parameters for the pipe, a parametric study is carried out with the objective of identifying a proper set of parameters for the NVA, which leads to a robust and effective vibration mitigation. It is shown that the methodology adopted herein allows for such identification to be made and that the suppression achieved with the selected NVA is one of the best among the results presented, even if supercritical internal flow velocities are considered. •A theoretical model of a flexible pipe discharging fluid with an NVA is developed.•The equations of motion are discretized using the Galerkin’s method.•A parametric study is made to select the NVA parameters to obtain robust suppression.•Mass additions alter the critical flow rate and destabilized mode of the pipe.•The NVA is able to bound the pipe dynamical response for supercritical flow rates.