Fairing and method
AssigneeStatoil Petroleum AS
InventorKjetil Skaugset
Life of this patent
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Abstract
A fairing device for the reduction of vortex-induced vibrations or motions, and for minimizing the drag about a substantially cylindrical element immersed in a fluid medium, comprising; a fairing rotatably mounted about the cylindrical element, the fairing comprising a shell with a mainly cylindrical cross-sectional shape with an outer diameter (D) following the outer diameter of the cylindrical element from an upward stagnation point of 0 degrees to at least +/−90 degrees, and which at +/−90 degrees continues as two fin-like portions in an aft direction, whereby the fin-like portions are convexly curved aft of +/−90 degrees thus tapering towards each other and are defining a tail end opening or gap less than the fairing standoff height. A method for mounting, storage, and deployment of the fairing device is also disclosed.
Claims21
A fairing device for the reduction of vortex-induced vibrations or motions and reduction of drag about a substantially cylindrical element immersed in a fluid medium, comprising:
- a fairing for mounting rotatably about said substantially cylindrical element, the fairing comprising a shell with a mainly cylindrical cross-sectional shape with an outer diameter (D) following the outer diameter of said cylindrical element from an upstream stagnation point of 0 degrees to at least +/−90 degrees, and which at +/−90 degrees continues in an aft direction as first and second fin-like portions,
- wherein the first and second fin-like portions are convexly curved aft of +/−90 degrees thus tapering towards each other and defining a tail end opening less than a standoff height of the fairing, wherein the first and second fin-like portions in the aft direction each define a chord length (C);
- wherein the chord length (C) of the first portion is dimensionally different than the chord length (C) of the second opposing portion, thus forming an asymmetric cross-section;
- and wherein the chord lengths of the first and second fin-like portions vary along the span length of the fairing.
A method for the mounting, storage and deployment of fairing devices for the reduction of vortex-induced vibrations or motions and minimization of drag about substantially cylindrical elements immersed in a fluid medium,
- characterized by the following steps:
- a) creating a plurality of joint sections prepared for storage by mounting fairing devices around respective cylindrical elements, wherein said fairing devices include first and second fin-like portions which are held in close proximity around the cylindrical elements;
- b) connecting the plurality of joint sections together prior to deployment into said fluid medium;
- c) actuating said fairing devices, thus bringing said first and second fin-like portions out from said close proximity around the cylindrical elements;
- and
- d) immersing a string comprising the plurality of connected joint sections into a fluid medium,
- wherein after actuating said fairing devices, said first and second fin-like portions define a chord length (C) in the aft direction on each side of the fairing devices;
- wherein the chord length (C) on a first side is dimensionally different than the chord length (C) on a second opposing side, thus forming an asymmetric cross-section;
- and wherein the chord length of each of the first and second fin-like portions varies along the span length of the fairing devices.
Dependencies are inferred from the claim text.