Profiled Cylindrical Surface for VIV and Drag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cylindrical objects in water environments, such as offshore drilling risers and pipelines, experience significant Vortex Induced Vibration (VIV) and drag due to asymmetric vortex formation, which current technologies like Matrix LGS and Helical Buoyancy systems do not adequately address.
Innovation Solution
A cylindrical element with an outer surface featuring hexagonal tessellations and groove arrangements that provide continuous 360-degree paths for water flow, creating multiple flow separation points and reducing VIV and drag by optimizing vortex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional smooth cylindrical surfaces are used, then manufacturing is simple, but VIV and drag are significant
Solution Approach 1:
The cylindrical surface is segmented into multiple discrete geometric features including protrusions, grooves, and ridges arranged in specific patterns. These segmented features disrupt the continuous surface, creating controlled flow separation points that reduce vortex formation and associated VIV and drag forces.
Solution Approach 2:
The invention employs asymmetric geometric profiles on the cylindrical surface, including non-uniform groove depths, varying protrusion shapes, and non-symmetric ridge configurations. These asymmetric features create intentional flow asymmetry that controls vortex shedding patterns, reducing the harmful VIV effects while maintaining structural integrity.
2Object-affected harmful factors
If helical grooves are added to reduce VIV, then VIV is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention transitions from static smooth surfaces to dynamic flow control features that adapt to flow conditions. The geometric profiles including grooves and protrusions create flow separation and reattachment patterns that dynamically respond to varying flow velocities and directions, effectively reducing VIV across a range of operating conditions.
Solution Approach 2:
The invention modifies surface geometric parameters including groove depth, width, spacing, and profile shape to optimize VIV reduction. By carefully selecting and varying these parameters, the design achieves effective vortex control while maintaining manufacturability through standardized fabrication processes for the geometric features.
3Reliability
If multiple VIV reduction devices are added, then VIV protection is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The cylindrical element with integrated geometric profiles serves multiple functions simultaneously: it provides VIV reduction, drag reduction, and structural support. The unified design eliminates the need for separate VIV protection devices, as the surface geometry itself performs the flow control function while maintaining the structural integrity of the cylindrical object.
Solution Approach 2:
The invention merges the VIV reduction functionality directly into the cylindrical surface structure by integrating geometric features like grooves, protrusions, and ridges into the base cylinder. This consolidation eliminates the need for additional external VIV protection devices, simplifying both the overall device complexity and installation procedures.
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 solution effectively minimizes VIV by up to 80% and reduces drag below 1.2 for specific Reynolds numbers, eliminating the need for additional VIV strakes and enhancing the structural integrity of submerged cylindrical structures.
Implementation Method 1
water flowing along a flow path within the groove arrangement from one side of the cylindrical element to another side of the cylindrical element will meet at least one flow separation point, wherein the flowing water is separated into a first flow path and a second flow path
Data Source
Figure 1~2
Figure 3
Figure 4A~4C
AI summary
A generally cylindrical element (10) that is adapted for immersion in water is described. The generally cylindrical element (10) has an outer surface (11) that is in contact with the water in use. The outer surface (11) has at least two rows of repeating shapes (20), for example hexagons (20), provided on the surface (11), where each row of repeating shapes (20) is separated from the other or the adjacent row(s) by a groove arrangement (30). Each shape (20) within a row is separated from the, or each, adjacent shape (20) by at least one groove (30). This configuration of the surface (11) reduces Vortex Induced Vibration (VIV) and/or drag that may act upon the generally cylindrical element (10) when it is immersed in a body of water.