Full Content is available to subscribers

Subscribe/Learn More  >

Dynamic Simulation of Offloading Operation Considering Wave Interaction Between Vessels

[+] Author Affiliations
Eduardo A. Tannuri, Tiago T. Bravin, Alexandre N. Simos, Karime H. Alves, Kazuo Nishimoto

University of São Paulo, São Paulo, SP, Brazil

Marcos D. Ferreira

Petrobras, Rio de Janeiro, RJ, Brazil

Paper No. OMAE2004-51118, pp. 245-250; 6 pages
  • ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering
  • 23rd International Conference on Offshore Mechanics and Arctic Engineering, Volume 1, Parts A and B
  • Vancouver, British Columbia, Canada, June 20–25, 2004
  • Conference Sponsors: Ocean, Offshore, and Arctic Engineering Division
  • ISBN: 0-7918-3743-2 | eISBN: 0-7918-3738-6
  • Copyright © 2004 by ASME


Almost all simulators of offshore systems evaluate wave forces using frequency-domain potential analysis. A wave analysis software is previously executed, considering several incidence angles and generating a data base which is used by the simulator. This database contains drift coefficients, RAOs and exciting forces for all incidences. During the simulation, the simulator only performs queries depending on the actual heading of the vessel related to waves. The simulation of multi-body systems cannot be performed in the same way, since the relative positions of the bodies change during simulation time, altering the influence of each ship on the overall wave field and its effect on the others. So, for each time step a new frequency-domain analysis should be performed, considering the vessel positions at that instant and updating the database used by the simulator. However, the computational effort necessary to perform such simulation turns this approach prohibitive for conventional computers and workstations. The wave forces are evaluated only in a predefined configuration of the vessels, or considering the vessels independently. Such approaches neglect all interactions and the complex dynamics behavior that results from it. The University of São Paulo has been developing since 2001, the Numerical Offshore Tank (NOT), a 120 processor cluster with the ability to perform detailed simulations considering bodies and lines dynamics very efficiently. In order to simulate offloading operations accurately, the commercial wave analysis software WAMIT was integrated to the NOT simulation code, allowing the “update” of wave coefficients data base every time the vessels configuration changes significantly. WAMIT code was adapted to perform parallel processing, greatly reducing the execution time and allowing the simulations to be performed in approximately 7 hours for the analysis of a 3-hour operation. Without WAMIT parallelization, this time would increase by a factor approximately equal to the number of wave frequencies considered in the simulation. This paper discusses the results obtained by the simulations of offloading operations in the presence of waves, detailing the effects that arise when the bodies interaction is taken into account. Effects are sensed in the equilibrium position, in the first order vertical motions and low-frequency oscillation.

Copyright © 2004 by ASME
Topics: Simulation , Waves , Vessels



Interactive Graphics


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

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