Reducing Vortex-Induced Vibration in Cylindrical Structures
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Summary
Problems
Cylindrical structures such as marine risers and pipelines experience vortex-induced vibration (VIV) and increased drag when immersed in fluid media, leading to reduced operating life due to fatigue, and existing flow modification devices are either impractical or time-consuming to deploy.
Innovation solutions
A cylindrical element with elongate bodies featuring raised body portions, such as curved or trapezoidal ridges, arranged along its length to reduce VIV and drag, eliminating the need for separate flow modification devices by integrating the structural features directly into the cylindrical element.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If helical strakes are used to reduce VIV, then VIV severity is reduced to very small levels, but the device becomes large and impractical to handle
Why choose this principle:
The helical strake is divided into multiple discrete spiral elements that can be independently deployed and stacked. Each spiral element is a separate component that attaches to the cylindrical structure, allowing for easier handling, deployment, and storage compared to a large continuous helical strake while maintaining VIV reduction effectiveness through the collective action of multiple segments
Principle concept:
If helical strakes are used to reduce VIV, then VIV severity is reduced to very small levels, but the device becomes large and impractical to handle
Why choose this principle:
The invention transitions from a two-dimensional surface modification to a three-dimensional volumetric structure by adding discrete spiral elements that extend outward from the cylindrical surface. This dimensional change allows the VIV protection features to be distributed in space, improving both effectiveness and deployability
Application Domain
Data Source
AI summary:
A cylindrical element with elongate bodies featuring raised body portions, such as curved or trapezoidal ridges, arranged along its length to reduce VIV and drag, eliminating the need for separate flow modification devices by integrating the structural features directly into the cylindrical element.
Abstract
A generally cylindrical element adapted for immersion in a fluid medium, the cylindrical element comprising an elongate body having a length and a generally circular cross-section, and a plurality of raised body portions disposed about and extending along the length of the elongate body, the raised body portions being arranged generally parallel to a longitudinal axis of the body and having a height between 2% and 10% of a diameter of the body. The plurality of raised body portions are adapted to reduce vortex-induced vibration and/or drag on the cylindrical element when the cylindrical element is immersed in the fluid medium and there is relative movement between the cylindrical element and the fluid medium.