0

Full Content is available to subscribers

Subscribe/Learn More  >

A Simplified Approach to Estimate Wake Oscillations in Riser Arrays

[+] Author Affiliations
Cédric Le Cunff

Principia, Houston, TX

Stéphane Toumit, Jean-Michel Heurtier

Principia, La Ciotat, France

Paper No. OMAE2011-49208, pp. 159-166; 8 pages
doi:10.1115/OMAE2011-49208
From:
  • ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering
  • Volume 7: CFD and VIV; Offshore Geotechnics
  • Rotterdam, The Netherlands, June 19–24, 2011
  • ISBN: 978-0-7918-4439-7
  • Copyright © 2011 by ASME

abstract

In the offshore industry, modeling pipe vibrations due to current is important to predict structural fatigue life. In the case of Wake Induced Oscillations (WIO), clashing is also an issue during the design phase to be able to define enough clearance to prevent clashing. If not possible, it is then needed to estimate contact energy between pipes and ensure that clashing is acceptable. Wake induced oscillations are difficult to predict, involving Vortex-Induced Vibrations (VIV) at relatively high frequency and small displacement together with larger motion at lower frequency leading to potential contact. A hydrodynamic model is proposed to predict WIO of a flexible pipe in the wake of an upstream pipe. The structural displacement of the two pipes is computed with a classical finite element model. The pipes are linked thru two dimensional strips where the hydrodynamic loads are computed based on the pipe distance in the strip. Since both pipes are flexible, the upstream pipe is subjected to VIV while the downstream pipe is subjected to the mean wake created by the pipe, to VIV as well as WIO. Each effect is represented by a simplified model. A Blevins model is used to represent the quasi-static drag and lift forces on the downstream riser. The VIV on the upstream riser is computed with a Van der Pol oscillator model, and a similar model is used for the downstream riser with an added term to account for the upstream riser presence. Experimental results on two tandem jumpers are used to validate the approach in steady current and in current plus wave. The database has a large number of model tests with different initial gaps between the two jumpers. Dynamic response of the two pipes is measured thru accelerometers and tension sensors. Some of the configurations exhibit clashing and/or overlapping of the jumpers. Amplitude and spectra of vibrations are compared to the proposed model; the general characteristics of the interaction (contact, overlapping) are also addressed.

Copyright © 2011 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In