KR20170021530A - Vortex Induced Vibration Reducing Structure and Riser having the Same - Google Patents

Vortex Induced Vibration Reducing Structure and Riser having the Same Download PDF

Info

Publication number
KR20170021530A
KR20170021530A KR1020150116024A KR20150116024A KR20170021530A KR 20170021530 A KR20170021530 A KR 20170021530A KR 1020150116024 A KR1020150116024 A KR 1020150116024A KR 20150116024 A KR20150116024 A KR 20150116024A KR 20170021530 A KR20170021530 A KR 20170021530A
Authority
KR
South Korea
Prior art keywords
riser
strut
reduction structure
vibration reduction
vortex
Prior art date
Application number
KR1020150116024A
Other languages
Korean (ko)
Inventor
김상연
전석희
오영태
정재훈
Original Assignee
대우조선해양 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 대우조선해양 주식회사 filed Critical 대우조선해양 주식회사
Priority to KR1020150116024A priority Critical patent/KR20170021530A/en
Publication of KR20170021530A publication Critical patent/KR20170021530A/en

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
    • F15D1/00—Influencing flow of fluids
    • F15D1/002—Influencing flow of fluids by influencing the boundary layer
    • F15D1/0025—Influencing flow of fluids by influencing the boundary layer using passive means, i.e. without external energy supply
    • F15D1/003—Influencing flow of fluids by influencing the boundary layer using passive means, i.e. without external energy supply comprising surface features, e.g. indentations or protrusions
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
    • F15D1/00—Influencing flow of fluids
    • F15D1/002—Influencing flow of fluids by influencing the boundary layer
    • F15D1/0025—Influencing flow of fluids by influencing the boundary layer using passive means, i.e. without external energy supply
    • F15D1/003—Influencing flow of fluids by influencing the boundary layer using passive means, i.e. without external energy supply comprising surface features, e.g. indentations or protrusions
    • F15D1/005—Influencing flow of fluids by influencing the boundary layer using passive means, i.e. without external energy supply comprising surface features, e.g. indentations or protrusions in the form of dimples
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems

Abstract

The present invention is further extended in analyzing the structure of the riser to include a vortex that reduces the effects of the vortex oscillation (VIV) and its fatigue damage among various causes of fatigue of the riser including geometry parameters A vibration reduction structure and a riser having such a reduction structure.
The vortex vibration reduction structure according to the present invention and the riser having such a reduction structure include at least one strake provided at a predetermined interval around a cylinder-shaped riser extending from the hull to the seabed; And a ring-shaped clamp which is provided at one or more intervals around the riser, wherein a shape capable of generating turbulence on the surface of the strut is further provided on the surface of the strut. do.

Description

[0001] The present invention relates to a vortex vibration reduction structure and a riser having such a reduction structure,

The present invention relates to a vortex vibration reduction structure and a riser having such a reduction structure that can reduce fatigue damage caused by vortices generated by currents when a cylindrical pipe-shaped riser is immersed in the ocean.

In recent years, oil and natural gas exploited in the seabed rather than land have been actively developed. The marine structures such as drillships, which are manufactured in the same form as general ships, are equipped with advanced drilling equipment, Has been developed and is being used for seabed drilling and production.

In order to drill oil or natural gas existing in a well, a riser or a drilling pipe can be moved up and down to a moonpool ).

Generally, the riser comprises a cylindrical pipe structure having flanges formed at both ends thereof, and the unit risers are coupled to each other and extend in the vertical direction by a required length to connect with the submarine well. These deep sea risers have a very complex dynamic behavior and an increasing importance on the behavior of the entire offshore structure system.

Therefore, it is necessary to analyze the mechanical damage of the riser placed in the deep-sea region, and it is necessary to analyze the damage of the riser placed in the fluid flow based on the analysis. Accordingly, the fatigue damage It is necessary to reduce the degree of influence.

These risers, when submerged in the ocean, generate vortices by currents. As a result, a pressure is applied to the cylindrical riser, and vortex induced vibration (VIV), in which the riser vibrates up and down due to the greatest pressure, occurs. Further, when an external force corresponding to the natural frequency of the riser is applied, resonance occurs, so that a larger pressure, a larger amplitude of vibration is applied to the riser, and thus there is more room for deformation of the riser, It will have a negative impact on the drilling system of ships or offshore structures.

In order to solve the above-mentioned problems, for example, a shape of the outer surface of the riser is modified by adding a strake of a helical structure to the surface of the riser or by giving a geometrical change such as a saw tooth to the outer surface of the riser, And so on.

However, such a method has a problem in that the process is complicated, for example, a strike is to be welded to the riser, the load space is insufficient because of the strake when loading the offshore structure, and the unit cost is increased.

Korean Patent Laid-Open Publication No. 10-2015-0052486 (Feb.

The Steel Catenary Riser in the Deep Sea Station is very long and relatively heavy, making it difficult to design. The fatigue damage is very vulnerable to risers, which are deep-sea resources for more than 20 years. Section. Therefore, the shape of the cylinder has a significant influence on the design of the riser.

Thus, the present invention can be further extended in analyzing the structure of the riser, including geometry parameters, to reduce the effects of the vortex oscillation (VIV) and its degree of fatigue damage among the various causes of fatigue to the riser And to provide a riser having such a reduction structure.

According to one aspect of the present invention, a strake is provided, which is provided at one or more intervals around a cylinder-shaped riser extending from a hull to a seabed; And a ring-shaped clamp provided around the riser at a predetermined interval, wherein a surface of the strut is further provided with a shape capable of generating turbulence on the surface of the strut, A vibration reduction structure is provided.

Preferably, the strake is fitted around the riser and can be easily detachable.

Preferably, the strake may be provided so as to be rotatable 360 degrees along the direction of the current flow.

Preferably, a plurality of dimples may be formed on the surface of the strut.

Preferably, the cross-section of the strut may be provided in a form capable of delaying a separation point.

Preferably, the cross section of the strut may be in the form of a streamlined droplet.

Preferably, the clamp may have a serrated shape.

According to another aspect of the present invention, there is provided a riser having a vortex vibration reduction structure as described above.

Preferably, the pressure acting in a direction perpendicular to the ocean current can be reduced by the vortex vibration reduction structure.

According to the present invention, it is possible to reduce vortex and vortex oscillations generated in the risers that negatively affect the riser and the ship or the offshore structure, thereby reducing the fatigue damage experienced by the riser in the deep sea, can do.

In addition, a streamlined strike, the least resistive type, can be applied to allow the riser to receive less resistance.

In addition, since the cylindrical shape is retained but the structure is fitted, the production process is simple, and the riser can be easily installed and assembled.

In addition, the cost can be reduced as compared with the conventional model for deforming the shape of the riser surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a structure of a vortex vibration reduction structure and a part of a riser according to an embodiment of the present invention; FIG.
2 schematically illustrates the structure of a vortex vibration reduction structure and the flow of cross sections and currents of a riser in accordance with an embodiment of the present invention.
3 is a front perspective view of a portion of a riser and a structure of a vortex vibration reduction in accordance with an embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings, which illustrate preferred embodiments of the present invention, and to the contents of the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The same elements are denoted by the same reference numerals even though they are shown in different drawings. In addition, the following examples can be modified in various forms, and the scope of the present invention is not limited to the following examples.

FIG. 1 is a schematic view illustrating a structure of a vortexer vibration reduction structure and a part of a riser according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a vortexor vibration reduction structure and a cross section of a riser according to an embodiment of the present invention. FIG. 3 is a front perspective view of a portion of a riser and a vortex vibration reduction structure in accordance with one embodiment of the present invention. FIG. 1, 2 and 3, respectively.

As shown in FIG. 1, the vortex vibration reduction structure according to the present invention is provided in a cylinder-shaped riser 100 extending from the hull to the seabed, and is provided at one or more intervals around the outer diameter of the riser 100 And a clamp 120 in the form of a ring.

The strut 110 and the clamp 120 are provided so as to fit around the outer diameter of the riser 100 and the cross section of the strut 110 has a separation point in the direction of the fluid, Should be provided in such a form as to be delayed to the rear of the riser 100.

A drag force is generated when an object touches a fluid, especially when the sphere lies on the fluid flow, a vortex occurs at the back of the sphere, and a force pulling back , That is, a drag force is generated. In addition, when the fluid particles pass through the sphere, the kinetic energy is lost due to the friction between the fluid and the sphere, so that the fluid does not follow the sphere fluid and peeling occurs.

The separation (or separation) refers to the separation of the fluid flow up and down as it hits an object placed in the flow. This point is called the separation point. At the separation point, part of the fluid flow falls into turbulence And the vibration of the object is caused by the difference of the kinetic energy.

In addition, the magnitude of this drag depends on the shape (cross-section) of the object. The drag force is proportional to the drag coefficient, the drag coefficient when the object is a plate type is about 2.0, the drag coefficient when it is spherical form is about 1.2, and the drag coefficient when it is droplet type is only about 0.12 .

Thus, if the cross-section of the object is a streamlined water droplet, the release point lies far behind the object (behind the flow of fluid) than when it is in plate or sphere form, thus reducing the magnitude of drag applied to the object It is.

Accordingly, it is most preferable that the strut 110 of the vortex vibration reduction structure 1 according to the present invention is provided in the form of a streamlined water droplet, as shown in Figs. That is, the cylinder shape of the riser 100 is maintained unchanged, and the strike 110 provided at the outer diameter of the riser 100 is provided in the form of a stream of water droplets. As shown in FIG. 2, The flow of seawater is naturally induced, whereby the separation point is delayed to the rear of the riser 100 to reduce the drag acting on the riser 100 and reduce the vibration. At this time, the peeling point is delayed behind the streamlined water droplet type strike 110 provided in the riser 100, so that it can be further moved away from the influence of the drag that the riser 100 receives.

In addition, the strut 110 includes a ring portion that can be fitted around the outer diameter of the riser 100, thus facilitating detachment and attachment, and facilitating the installation, assembly, and loading of the riser.

The strut 110 fitted around the outer diameter of the riser 100 is fixed in the vertical position by the clamp 120 and one or more strut 110 is sandwiched between the two clamps 120.

Likewise, the clamp 120 may be provided to secure the strut 110 so that it does not move vertically about the outer diameter of the riser 100, but may be provided in an annular form so as to fit around the outer diameter of the riser 100 do. At this time, the peripheral shape of the clamp 120 may be provided in a non-smooth deformed shape, for example, in a serrated shape so as to reduce the influence of the eddy current vibration due to the current.

3, the strut 110 is fitted to the riser 100 and is provided so as to be rotatable 360 degrees along the direction of the current flow. That is, even if the sea current is in a sea environment in which the direction of the ocean current is changed instantaneously, that is, regardless of which direction the sea water flows, the strike 110 can rotate freely with the riser 100 remaining thereon, .

In addition, the strut 110 may further include a structure in which seawater does not flow constantly, that is, turbulent flow is generated on the surface of the strut 110. For example, as shown in FIG. 1, Can be provided.

By providing a plurality of grooves called dimples 111 on the surface of the strut 110, it is possible to generate turbulence in which the seawater does not flow constantly on the surface of the strut 110. These turbulent flows are intermixed with each other so that intermolecular energy transfer is easy. Therefore, the relatively high velocity fluid outside the boundary layer of the sea water flow is mixed with the relatively slow velocity fluid in the boundary layer, so that the kinetic energy of the fluid at a high velocity is transferred to the fluid at a low velocity, do.

This principle amplifies the effect of retarding the flow backward, that is, the point at which the flow velocity becomes zero, to the rear side of the object, that is, the strike 110 provided on the riser 100.

As described above, in the vortex vibration reduction structure 1 according to the embodiment of the present invention, the strike 110 having a streamlined water droplet shape is inserted into the riser 100 together with the serrated clamp 120 And a plurality of dimples 111 are provided on the surface of the strut 110. The strut 110 is freely rotatable in accordance with the direction of the current, It is easy to install and can delay the peeling point of the riser 100 on the sea water flow in the sea, and the effect of the pressure acting on the riser 100 in the vertical direction to the current, that is, The fatigue damage caused by the fatigue crack can be reduced.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. . Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and thus the invention is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

1: Vortex vibration reduction structure
100: riser
110: strake
111: dimple (dimple)
120: Clamp

Claims (9)

At least one strake provided at a predetermined interval around a cylinder-shaped riser extending from the hull to the seabed; And
And at least one ring-shaped clamp provided at a predetermined interval around the riser,
Wherein the surface of the strut is further provided with a shape capable of generating turbulence on the surface of the strut. The method according to claim 1,
Wherein the strake is fitted around the riser and is easy to attach and detach. The method of claim 2,
Wherein the strakes are provided so as to be 360 占 rotatable along the direction of the current flow. The method of claim 3,
And a plurality of dimples are formed on a surface of the strut. The method of claim 4,
Wherein a cross section of the strut is provided in a form capable of delaying a separation point. The method of claim 5,
Wherein the cross-section of the strut is in the form of a streamlined water droplet. The method of claim 3,
Wherein the clamp has a sawtooth shape. A riser with a vortex vibration reduction structure according to claims 1 to 7. The method of claim 8,
A riser having a vortex vibration reduction structure in which the pressure acting in a direction perpendicular to the current is reduced by the vortex vibration reduction structure.
KR1020150116024A 2015-08-18 2015-08-18 Vortex Induced Vibration Reducing Structure and Riser having the Same KR20170021530A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020150116024A KR20170021530A (en) 2015-08-18 2015-08-18 Vortex Induced Vibration Reducing Structure and Riser having the Same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150116024A KR20170021530A (en) 2015-08-18 2015-08-18 Vortex Induced Vibration Reducing Structure and Riser having the Same

Publications (1)

Publication Number Publication Date
KR20170021530A true KR20170021530A (en) 2017-02-28

Family

ID=58543273

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150116024A KR20170021530A (en) 2015-08-18 2015-08-18 Vortex Induced Vibration Reducing Structure and Riser having the Same

Country Status (1)

Country Link
KR (1) KR20170021530A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107916899A (en) * 2017-11-24 2018-04-17 西南石油大学 A kind of vortex-induced vibration suppression device and method of the rotatable wavy orifice plate in change aperture
CN109869567A (en) * 2019-04-04 2019-06-11 中国石油大学(华东) A kind of changeable-shaped marine oil and gas tubing string vortex-induced vibration suppression device
KR20190073161A (en) 2017-12-18 2019-06-26 대우조선해양 주식회사 Vortex induced vibration reducing apparatus
KR20190091955A (en) * 2018-01-30 2019-08-07 한국해양대학교 산학협력단 Vortex induced vibration reduction device of offshore structure
CN113432832A (en) * 2021-06-24 2021-09-24 哈尔滨工程大学 Test device for measuring flow-induced noise and vortex-induced noise of marine pipeline

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150052486A (en) 2013-11-06 2015-05-14 대우조선해양 주식회사 Apparatus for damping and generating vortex induced vibration of ocean riser, and vessel or ocean construction comprising the same

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150052486A (en) 2013-11-06 2015-05-14 대우조선해양 주식회사 Apparatus for damping and generating vortex induced vibration of ocean riser, and vessel or ocean construction comprising the same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107916899A (en) * 2017-11-24 2018-04-17 西南石油大学 A kind of vortex-induced vibration suppression device and method of the rotatable wavy orifice plate in change aperture
KR20190073161A (en) 2017-12-18 2019-06-26 대우조선해양 주식회사 Vortex induced vibration reducing apparatus
KR20190091955A (en) * 2018-01-30 2019-08-07 한국해양대학교 산학협력단 Vortex induced vibration reduction device of offshore structure
CN109869567A (en) * 2019-04-04 2019-06-11 中国石油大学(华东) A kind of changeable-shaped marine oil and gas tubing string vortex-induced vibration suppression device
CN113432832A (en) * 2021-06-24 2021-09-24 哈尔滨工程大学 Test device for measuring flow-induced noise and vortex-induced noise of marine pipeline
CN113432832B (en) * 2021-06-24 2023-01-03 哈尔滨工程大学 Test device for measuring flow-induced noise and vortex-induced noise of marine pipeline

Similar Documents

Publication Publication Date Title
EP2049805B1 (en) Twin fin fairing
KR20170021530A (en) Vortex Induced Vibration Reducing Structure and Riser having the Same
Huang VIV suppression of a two-degree-of-freedom circular cylinder and drag reduction of a fixed circular cylinder by the use of helical grooves
AU2005241044B2 (en) Tail fairing designed with features for fast installation, apparatus incorporating such fairings, methods of making and using such fairings and apparatus, and methods of installing such fairings
US20090133612A1 (en) Dynamic motion suppression of riser, umbilical and jumper lines
US8029210B2 (en) Methods and apparatus for installation of VIV suppression during installation of marine pipeline
US20070125546A1 (en) Strake systems and methods
WO2008064102A2 (en) Systems and methods for reducing drag and/or vortex induced vibration
CN106869821B (en) A kind of adaptive vortex-induced vibration suppression device with assistant shape ribbon
GB2448663A (en) Flexible net like fairing for riser
KR102455878B1 (en) Vortex induced vibration reducing apparatus
WO2011022332A1 (en) Vortex induced vibration suppression systems and methods
EP3314083B1 (en) A flow modification device, system, and method
CN211820218U (en) Marine pipeline vortex-induced vibration suppression device with ribbons
AU2016282215A1 (en) A cylindrical element adapted to reduce vortex-induced vibration and/or drag
Lin et al. Experimental investigation of a new device in suppressing vortex-induced vibrations of a circular cylinder
US20090242207A1 (en) Strake systems and methods
KR20130113704A (en) Riser and installing method thereof
Allen et al. VIV suppression device development and the perils of Reynolds number
Freire et al. Defining a parameter of effectiveness for the suppression of vortex-induced vibration
Sergent et al. Vortex Induced Vibration of the GAP Bundle: From Selection of Flow Lines Arrangement to VIV Fatigue Analysis
KR102015212B1 (en) Vortex induced vibration reduction device of offshore structure
US11359651B2 (en) Flow modification device having helical strakes and a system and method for modifying flow
WO2009046166A1 (en) Systems and methods for reducing drag and/or vortex induced vibration
Huang et al. Experimental Study of Wake Shielding Effects of Three Cylinders in Currents