Fluid nonlinearities effect on wake oscillator model performance

Victoria Kurushina, Ekaterina Pavlovskaia

Research output: Contribution to journalArticle

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Abstract

Vortex-induced vibrations (VIV) need to be accounted for in the design of marine structures such as risers and umbilicals. If a resonance state of the slender structure develops due to its interaction with the surrounding fluid flow, the consequences can be severe resulting in the accelerated fatigue and structural damage. Wake oscillator models allow to estimate the fluid force acting on the structure without complex and time consuming CFD analysis of the fluid domain. However, contemporary models contain a number of empirical coeffcients which are required to be tuned using experimental data. This is often left for the future work with the opened question on how to calibrate a model for a wide range of cases and find out what is working and is not. The current research is focused on the problem of the best choice of the fluid nonlinearities for the base wake oscillator model [1] in order to improve the accuracy of prediction for the cases with mass ratios around 6.0. The paper investigates six nonlinear damping types for two fluid equations of the base model. The calibration is conducted using the data by Stappenbelt and Lalji [2] for 2 degrees-of-freedom rigid structure for mass ratio 6.54. The conducted analysis shows that predicted in-line and cross-flow displacements are more accurate if modelled separately using different damping types than using only one version of the model. The borders of application for each found option in terms of mass ratio are discussed in this work, and appropriate recommendations are provided.

Original languageEnglish
Article number04002
Number of pages6
JournalMATEC Web of Conferences
Volume148
DOIs
Publication statusPublished - 2 Feb 2018
EventInternational Conference on Engineering Vibration - Sofia, Bulgaria
Duration: 4 Sep 20177 Sep 2017
http://www.icoev2017.org/

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Fluids
Damping
Rigid structures
Ocean structures
Flow of fluids
Computational fluid dynamics
Vortex flow
Fatigue of materials
Calibration

Keywords

  • Computational fluid dynamics
  • Damping
  • Degrees of freedom (mechanics)
  • Fatigue damage
  • Flow of fluids
  • Marine Risers
  • Nonlinear equations
  • Offshore structures
  • Oscillators (mechanical)
  • Wakes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Engineering(all)

Cite this

Fluid nonlinearities effect on wake oscillator model performance. / Kurushina, Victoria; Pavlovskaia, Ekaterina.

In: MATEC Web of Conferences, Vol. 148, 04002, 02.02.2018.

Research output: Contribution to journalArticle

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