Design of the Truss Spars for the Nansen/Boomvang Field Development

Bangs, A S; Miettinen, J.A.; Silvola, Ilari; Mikkola, Timo; Beattie, S. Michael

doi:10.4043/14090-ms

Cited by 12 publications

(9 citation statements)

References 2 publications

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“…Evaluation of vortex induced motion (VIM) in offshore floating structures has been largely been carried out for spars. Classic spar, truss spar and cell spar hulls are all known to exhibit VIV (VIM) [1], [2], [6], [7], [8], [9], [10], [12], [13], [14], [15], [16], [19], [27], [28], [29]. [31], [32],…”

Section: Introductionmentioning

confidence: 99%

Flow Induced Motions on Multi Column Floaters

Waals

Phadke

Bultema³

2007

Volume 1: Offshore Technology; Special Symposium on Ocean Measurements and Their Influence on Design

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Recent years have shown an increasing interest in low frequency response of offshore floaters in current. Spar VIM behavior and Semi Submersible flow induced behavior is known from calm water tow tests. Recent tow test projects have also shown low frequency TLP response in steady current. The motions from the model tests are used in the global analysis of the mooring systems and risers for these platforms. This paper discusses the dynamic behavior in current of multi column floaters and the associated complex flow patterns. Shielding between columns is addressed as well as the effect of mass ratio (i.e. floater mass divided by displacement). It is shown that lower mass ratios such as for conventional TLP’s may result in larger sway response than for deep draft semi submersibles. The motion behavior is discussed as well as the increase in total mean current loads due to transverse motions.

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Section: Introductionmentioning

confidence: 99%

Flow Induced Motions on Multi Column Floaters

Waals

Phadke

Bultema³

2007

Volume 1: Offshore Technology; Special Symposium on Ocean Measurements and Their Influence on Design

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“…In all cases the spars float vertically, and are held in place by mooring lines which are attached close to mid-draft of the hull. More details on these spar design may be found in [1,2,3].…”

Section: Introductionmentioning

confidence: 99%

Benchmarking of Truss Spar Vortex Induced Motions Derived From CFD With Experiments

Halkyard

Sirnivas

Holmes

et al. 2005

24th International Conference on Offshore Mechanics and Arctic Engineering: Volume 3

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Floating spar platforms are widely used in the Gulf of Mexico for oil production. The spar is a bluff, vertical cylinder which is subject to Vortex Induced Motions (VIM) when current velocities exceed a few knots. All spars to date have been constructed with helical strakes to mitigate VIM in order to reduce the loads on the risers and moorings. Model tests have indicated that the effectiveness of these strakes is influenced greatly by details of their design, by appurtenances placed on the outside of the hull and by current direction. At this time there is limited full scale data to validate the model test results and little understanding of the mechanisms at work in strake performance. The authors have been investigating the use of CFD as a means for predicting full scale VIM performance and for facilitating the design of spars for reduced VIM. This paper reports on the results of a study to benchmark the CFD results for a truss spar with a set of model experiments carried out in a towing tank. The focus is on the effect of current direction, reduced velocity and strake pitch on the VIM response. The tests were carried out on a 1:40 scale model of an actual truss spar design, and all computations were carried out at model scale. Future study will consider the effect of external appurtenances on the hull and scale-up to full scale Reynolds’ numbers on the results.

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“…Out of the 17 Spar platforms installed worldwide, almost all of them were deployed in the Gulf of Mexico (GOM).Therefore, numerous studies similar to those mentioned early were carried out in the GOM, such as studies by Bangs et al (2002), and some studies were conducted in the West Africa such as those by Wang et al (2002). Only a few technical papers focused on the Spar platform deployed in SCS.…”

Section: Introductionmentioning

confidence: 94%

Numerical study on global motion of Truss Spar in frequency and time domains for the Liwan 3-1 area

2011

J. Ocean Univ. China

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Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m in the Liwan 3-1 area of the South China Sea. Firstly, the seakeeping ability is acquired in the frequency domain by calculating the hull's hydrodynamics and comparing with a semi-submersible platform. The random wave analysis for 100-year, 10-year and 1-year return periods in Liwan 3-1 distinctly shows lower heave but larger surge and pitch responses of the Truss Spar than those of a semi-submersible. Secondly, 3-hour motions of the Truss Spar are predicted and compared in the time domain under 100-year return period conditions in Liwan 3-1 and the Gulf of Mexico. Thirdly, the hull/mooring line coupled and uncoupled models are compared. Finally, the responses of the Truss Spar under 10-year and 1-year return period conditions are assessed. The results reveal that the mooring line damping reflected by the coupled model distinctly decreases the low frequency motion. The maximum heave response for 100-year return period waves is 1.23m and below 0.1m for the case of 1-year return period.

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Design of the Truss Spars for the Nansen/Boomvang Field Development

Cited by 12 publications

References 2 publications

Flow Induced Motions on Multi Column Floaters

Flow Induced Motions on Multi Column Floaters

Benchmarking of Truss Spar Vortex Induced Motions Derived From CFD With Experiments

Numerical study on global motion of Truss Spar in frequency and time domains for the Liwan 3-1 area

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