Flexible VIV Strake Fin Structure for Subsea Conduit Installation

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Solution Overview

Problem

Subsea conduits, such as pipelines or cables, experience vortex-induced vibrations due to sea currents, leading to fatigue damage.

Innovation Solution

A vortex-induced vibration (VIV) strake arrangement comprising a VIV strake shell and a VIV strake fin with flexible legs that define a void, allowing the legs to temporarily flex and avoid damage during conduit installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid strake fin is used to suppress vortex-induced vibrations, then vibration suppression effectiveness is improved, but the fin tip may accumulate fatigue damage during conduit installation due to temporary flexing

Engineering Contradiction:

Improvevibration suppression effectivenessVSAvoidfin tip durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The fin tip material properties are changed from rigid to flexible, allowing temporary flexing during installation without permanent deformation or fatigue damage. This parameter change enables the fin to maintain vibration suppression functionality while accommodating installation stresses.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The flexible fin tip design anticipates and accommodates temporary flexing stresses that occur during conduit installation by allowing reversible deformation. This beforehand cushioning prevents permanent damage or fatigue accumulation that would occur with a rigid fin design.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If the strake fin design is simplified for ease of manufacture, then manufacturing complexity is reduced, but the ability to accommodate installation stresses is compromised

Engineering Contradiction:

Improvestrake fin manufacturing simplicityVSAvoidinstallation stress accommodation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The fin tip is designed as a flexible component that can be manufactured from elastomeric materials. This flexible shell approach provides both manufacturing simplicity and the necessary stress accommodation capability during installation.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The strake fin incorporates composite construction with a rigid support structure and a flexible fin tip made from elastomeric material. This composite design achieves both ease of manufacture and reliability during installation by combining materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The VIV strake arrangement effectively suppresses vortex-induced vibrations, reducing the risk of fatigue damage to subsea conduits and ensuring the longevity of the installation.

Implementation Method 1

a flexible fin tip, flexible first and second legs extending from the flexible fin tip

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

VIV strake arrangement for mitigating vibration of subsea conduits caused by vortex-induced vibrations

Methodology Applied

Scientific EffectVortex-induced vibration mitigation: Kármán Vortex Street

Data Source

PatentUS20250146599A1Vortex-induced vibration strake arrangements

Publication Date: 2025.05.08 ADVANCED INSULATION LTD

AI summary

A vortex-induced vibration (VIV) strake arrangement is provided. The VIV strake arrangement comprises: a VIV strake shell for location on a conduit; and a VIV strake fin, for coupling to the VIV strake shell, comprising a flexible fin tip, a flexible first leg extending from the flexible fin tip and a flexible second leg extending from the flexible fin tip, wherein the VIV strake fin is shaped such that when the VIV strake fin is connected to the VIV strake shell and the VIV strake shell is located on the conduit, the flexible first and second legs extend from the flexible fin tip and define a void between the flexible first and second legs.