Comparison of dynamical responses of an offshore riser with linear and nonlinear structural characteristics through nonlinear normal modes

Marko Keber*, Marian Wiercigroch

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

This work investigates the effect of structural nonlinearity on the oscillations of an offshore riser subjected to vortex-induced vibration. The riser is modelled by a vertical pipe with steady internal flow which has no direct nonlinear influence on the motion of the coupled system of the structure and fluid surrounding it. The only excitation in the model comes from the pressure difference on the riser arising as a result of vortex-shedding behind its cylindrical body. Simulations of dynamical responses in modal space were performed for two similar models in order to show how a weak geometrical nonlinearity influences oscillations of the riser and consequently the lift coefficient governing forcing from external flow. The structure in the first model had purely linear characteristics, while a nonlinear axial strain relation was introduced in the second one. Comparing responses of the two models, it was found that effects the nonlinearity had on the oscillation were considerably greater when internal flow was included in the calculation as opposed to when the riser was an empty pipe.

Original languageEnglish
Title of host publicationOCEANS 2007 - Europe
PublisherIEEE Explore
ISBN (Print)1424406358, 9781424406357
DOIs
Publication statusPublished - 28 Nov 2007
EventOCEANS 2007: Europe - Aberdeen, United Kingdom
Duration: 18 Jun 200721 Jun 2007
https://www.tib.eu/en/search/id/TIBKAT%3A557478170/ (Link to Conference proceedings from TIB)

Conference

ConferenceOCEANS 2007: Europe
CountryUnited Kingdom
CityAberdeen
Period18/06/0721/06/07
Internet address

Fingerprint

riser
Normal Modes
Internal Flow
nonlinearity
Oscillation
oscillation
Vortex-induced Vibration
Pipe
Nonlinearity
Geometrical Nonlinearity
Vortex Shedding
pipe
Vortex shedding
vortex shedding
Steady Flow
Model
Coupled System
Forcing
Vortex flow
Excitation

ASJC Scopus subject areas

  • Computer Science Applications
  • Oceanography
  • Ocean Engineering
  • Modelling and Simulation

Cite this

Comparison of dynamical responses of an offshore riser with linear and nonlinear structural characteristics through nonlinear normal modes. / Keber, Marko; Wiercigroch, Marian.

OCEANS 2007 - Europe. IEEE Explore, 2007. 4302410.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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