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Lookup NU author(s): Yibo Liang, Professor Longbin Tao
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
A numerical study on the flow over a deep-draft semi-submersible (DDS) for both stationary and vortex-induced motions (VIM) was carried out using the computational fluid dynamics (CFD), with the aim to investigate the overall hydrodynamics of the structure. In order to study the fluid physics associated with VIM, a comprehensive numerical simulation was conducted to examine the characteristics of vortex formations, shedding processes and especially their interactions due to the multiple cylindrical columns. In addition to the vortex shedding characteristics, the drag and lift forces on each member of the overall structure were calculated. It is revealed that under 45 degree incidence, the transverse forces induced by the portside and starboard side columns are the dominant excitation forces responsible to VIM while the horizontal member - pontoons restraining VIM. In addition, the hysteresis phenomenon observed between the force and motion domains - the peak lift force occurs slightly earlier than the peak transverse motion is mainly due to the vortices shed from the upstream column move back to impinge on one of the side columns after impinging on the other side column and the symmetrical strong vortices which shed from the side columns.
Author(s): Liang Y, Tao L
Publication type: Article
Publication status: Published
Journal: Ocean Engineering
Year: 2017
Volume: 141
Pages: 427-449
Print publication date: 01/09/2017
Online publication date: 05/07/2017
Acceptance date: 23/06/2017
Date deposited: 24/07/2017
ISSN (print): 0029-8018
ISSN (electronic): 1873-5258
Publisher: Elsevier
URL: https://doi.org/10.1016/j.oceaneng.2017.06.056
DOI: 10.1016/j.oceaneng.2017.06.056
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