Full-scale CFD investigations of helical strakes as a means of reducing the vortex induced forces on a semi-submersible

Download

index.pdf

Date

2017-06-01

Author

Holland, Vegard
Tezdogan, Tahsin
Oğuz, Elif

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

88
views

79
downloads

As the search for oil in the Gulf of Mexico (GoM) moves into deeper waters, floating platforms such as semi-submersibles 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.

Subject Keywords

Helical strake, CFD, Semi-submersible, Vortex-induced motion

URI

https://hdl.handle.net/11511/40927

Journal

OCEAN ENGINEERING

DOI

https://doi.org/10.1016/j.oceaneng.2017.04.014

Collections

Department of Civil Engineering, Article

Suggestions

OpenMETU
Core

An Experimental study of enhanced oil recovery application in limestone medium using NaOH solutions Ay, Cansu; Sınayuç, Çağlar; Department of Petroleum and Natural Gas Engineering (2014) An interest in enhanced oil recovery is increasing due to rising oil prices, rising energy consumption and insufficient oil production from conventional techniques. As an EOR technique, alkaline injection is widely used to recover the trapped oil in pore spaces. In this study,the use of sodium hydroxide (NaOH) solutions as an enhanced oil recovery technique for limestone formations in South East Turkey was investigated. Routine core analyses (porosity, permeability and grain density) and spontaneous imbibit...
The Use of capacitance-resistive models for estimation of interwell connectivity & heterogeneity in a waterflooded reservoir: a case study Gözel, Mustafa Erkin; Akın, Serhat; Department of Petroleum and Natural Gas Engineering (2015) Increasing the oil recovery from the hydrocarbon reservoirs is becoming the most important issue for the oil & gas industry with the increase in energy demand and developing technologies. Waterflooding is one of the most preferable methods because of its success ratio, application ease and cost efficiency. Beside mentioned advantages, this method must be carefully planned and performed by considering reservoir heterogeneities to avoid unexpected poor recoveries. As an alternative to the reservoir modeling a...
An Experimental investigation of the shale inhibition properties of a quaternary amine compound Taş, Baki Tuğrul; Sınayuç, Çağlar; Gücüyener, İsmail Hakkı; Department of Petroleum and Natural Gas Engineering (2013) Depleting oil reserves and increased costs of the oil and gas recoveries have created the need to drill in challenging formations. When drilled through, shale formations in particular always generated a wide variety of problems if conventional water-based muds are used. Furthermore, the complexity and variations in shales have compounded the task of developing suitable drilling fluids. In light of these problems, the study of shale properties and their interactions with fluids will continue to be a muchneed...
A wave climate study for an LNG terminal near Marmara Ereglisi, Turkey Akyarli, A; Yalçıner, Ahmet Cevdet (1997-01-01) A liquefied natural gas (LNG) terminal has been constructed near Marmara Ereglisi - a coastal town located at the northern coast of the Sea of Marmara in Turkey - to unload imported LNG from Algeria. Regarding the wave related issues in the design of the terminal and offshore operations, a wave climate study - comprising direct wave measurements carried out by a directional type wave buoy during one year period and hindcasting studies based on ten years of hourly wind data recorded at Tekirdag meteorologica...
Investigation of gas hydrate potential of the Black Sea and modelling of gas production from a hypothetical Class 1 methane hydrate reservoir in the Black Sea conditions Merey, Sukru; Sınayuç, Çağlar (2016-02-01) Gas hydrate deposits which are found in deep ocean sediments and in permafrost regions are supposed to be a fossil fuel reserve for the future. The Black Sea is also considered rich in terms of gas hydrates. It abundantly contains gas hydrates as methane (CH4 similar to 80-99.9%) source. In this study, by using the literature seismic and other data of the Black Sea such as salinity, porosity of the sediments, common gas type, temperature distribution and pressure gradient, it was estimated that up to 71.8 (...

Citation Formats

V. Holland, T. Tezdogan, and E. Oğuz, “Full-scale CFD investigations of helical strakes as a means of reducing the vortex induced forces on a semi-submersible,” OCEAN ENGINEERING, pp. 338–351, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40927.