FIV2018 Paper Management System, FIV2018 Conference

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A numerical study of VIV suppression using a rotative NES (Non-linear Energy Sink) and a wake-oscillator model
Tatiana Ueno, Guilherme Rosa Franzini, Beatriz Sayuri Sato

Last modified: 2018-06-25

Abstract


Vortex-Induced Vibrations (VIV) is a self-excited and self-limited fluid-structure interaction problem that plays a key-role on riser dynamics. VIV suppression is an important aspect of the theme. Examples of suppressors are the strakes and the splitter-plates. These suppressors are in contact with the external flow. Conversely, there is another type of passive suppressors named NES (Non-linear Energy Sink), internally assembled to the main structure through a dashpot and characterized by an intrinsic non-linear dynamic. In this paper, a particular class of NES named as rotative NES is numerically studied as a suppressor for the VIV of a rigid and elastically supported cylinder. This NES is defined by a rigid rod with a tip-mass, free to rotate around the cylinder axis and coupled to the main structure by a linear dashpot. The cylinder is constrained to oscillate in the cross-wise direction and the hydrodynamic loads are computed using a wake-oscillator model.  In the full paper, the response of the system composed of the cylinder and of the suppressor will be investigated as functions of the parameters that define the NES such as its mass, radius and dashpot constant for different reduced velocities.


Keywords


VIV suppression; Non-linear Energy Sink; wake-oscillator model; numerically investigation

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