Full-scale CFD investigations of helical strakes as a means of reducing the vortex induced forces on a semi-submersible
Holland, Vegard and Tezdogan, Tahsin and Oguz, Elif (2017) Full-scale CFD investigations of helical strakes as a means of reducing the vortex induced forces on a semi-submersible. Ocean Engineering, 137. pp. 338-351. ISSN 0029-8018 (https://doi.org/10.1016/j.oceaneng.2017.04.014)
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Abstract
As the search for oil in the Gulf of Mexico (GoM) moves into deeper waters, floating platforms such as semisubmersibles are in increasing demand. As semi-submersibles increase in size, the effect of vortex-induced motions (VIMs) becomes a significant problem in their design. VIMs stem from transverse forces caused by the current affecting the platform, with vortexes moving downstream on either side of the structure. The loop/eddy current phenomenon in the GoM leads to a constant current being present in the area, with speeds of up to 1.8 m/s. The accurate prediction of the vertical and transverse motions of semi-submersibles is crucial for the design of the riser systems. It is therefore beneficial to investigate the hydrodynamic forces acting on the geometry, and means of reducing these forces. A common method of reducing transverse forces is the addition of column appendages, such as helical strakes. In this paper, full-scale computational fluid dynamic analyses are carried out to examine the transverse forces caused by this vortex shedding using realistic current velocities in the GoM. Helical strakes are attached to the geometry to break up the coherence of the vortex shedding and the performance of these strakes is investigated numerically.
ORCID iDs
Holland, Vegard, Tezdogan, Tahsin ORCID: https://orcid.org/0000-0002-7032-3038 and Oguz, Elif ORCID: https://orcid.org/0000-0003-3574-9436;-
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Item type: Article ID code: 60458 Dates: DateEvent18 April 2017Published13 April 2017AcceptedSubjects: Technology > Hydraulic engineering. Ocean engineering Department: Faculty of Engineering > Naval Architecture, Ocean & Marine Engineering Depositing user: Pure Administrator Date deposited: 18 Apr 2017 11:15 Last modified: 25 Oct 2024 18:20 Related URLs: URI: https://strathprints.strath.ac.uk/id/eprint/60458