VIV of flexible structures in 2D uniform flow.

Kurushina, Victoria; Pavlovskaia, Ekaterina; Wiercigroch, Marian

Abstract

The paper investigates Vortex-Induced Vibration (VIV) of a horizontal flexible structure with pinned-pinned ends in uniform flow. The fluid–structure interaction is modelled using the wake oscillator approach to describe fluctuations of the fluid forces, based on results previously reported by Pavlovskaia et al. (2016), Postnikov (2016), and Kurushina et al. (2018). New two-dimensional wake oscillator models are developed in this study, employing a number of alternative damping types in the fluid equation. The proposed models are calibrated with the experimental data published by Sanaati and Kato (2012) for VIV of a horizontal flexible structure for the middle cross-section. The calibration is performed with a focus on the maximum of the observed displacement amplitude in the cross-flow direction. The fact that one of the models had the Van der Pol-Krenk–Nielsen damping made it possible to achieve the lowest objective function during the calibration and this, therefore, was selected for the detailed analysis in 3 and 5 mode approximations. The dynamics of this model are considered in terms of the time histories, changes in the standard deviations of the modal coefficients along the reduced velocity range and frequency response. Also provided is a comparison with the alternative model versions, in terms of the displacements generated at different locations. In contrast to the previous findings by Kurushina et al. (2018) for VIV of rigid structures, for the flexible structures it was found in this study that both Van der Pol and Rayleigh damping types appear to be applicable for VIV prediction. A detailed consideration of the 3 mode approximation of the Krenk–Nielsen–Van der Pol model reveals a presence of co-existing solutions in a number of regions of the reduced velocity. They are present in short ranges of reduced velocity in between the lock-in peaks of the in-line displacement coefficient of the first mode. Modulations and co-existing solutions in the in-line modal coefficients make the in-line displacement prediction challenging, while the cross-flow displacement amplitudes are described reasonably well by the proposed models.

Citation

KURUSHINA, V., PAVLOVSKAIA, E. and WIERCIGROCH, M. 2020. VIV of flexible structures in 2D uniform flow. International journal of engineering science [online], 150, article number 103211. Available from: https://doi.org/10.1016/j.ijengsci.2019.103211

• Journal Article Type: Article
• Acceptance Date: Dec 25, 2019
• Online Publication Date: Mar 19, 2020
• Publication Date: May 31, 2020
• Deposit Date: Feb 13, 2024
• Publicly Available Date: Feb 29, 2024
• Journal: International journal of engineering science
• Print ISSN: 0020-7225
• Electronic ISSN: 1879-2197
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 150
• Article Number: 103211
• DOI: https://doi.org/10.1016/j.ijengsci.2019.103211
• Keywords: Vibration; Fluid dynamics; Flexible structures
• Public URL: https://rgu-repository.worktribe.com/output/2166762