Helical Strake Shell-and-Fin Assembly for Tubular VIV Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in the oil and gas industry is managing ocean currents, which cause vortex-induced vibration (VIV) and deflections in tubulars, leading to fatigue damage and suspension issues, and existing helical strakes are costly to produce in moderate or low quantities, especially when banded fins are used.
Innovation Solution
A method for fabricating helical strakes with a shell and discrete fins, where the shell is dimensioned to encircle the tubular with fin openings, and fins are positioned within these openings in a helical arrangement, allowing for cost-effective production and suppression of VIV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complete mold is produced for manufacturing helical strakes with shells, then manufacturing precision and reliability are improved, but manufacturing cost increases significantly for moderate or low production quantities
Solution Approach 1:
The invention divides the helical strake into discrete components: a shell structure with fin openings and separate fin elements. This segmentation allows the shell to be manufactured independently using cost-effective methods for moderate/low quantities, while fins can be attached subsequently. The modular approach eliminates the need for expensive complete molds while maintaining assembly precision through standardized opening dimensions and fin attachment protocols.
2Ease of manufacture
If banded fins are used to eliminate the shell, then manufacturing cost is reduced, but construction difficulty increases
Solution Approach 1:
The shell structure serves as an intermediary component that simplifies the overall construction process. By providing a pre-formed shell with precisely positioned fin openings, the invention eliminates the complexity of directly banding fins to the tubular. The shell acts as a mounting platform that standardizes fin attachment, reducing construction difficulty while maintaining cost-effectiveness compared to complete mold manufacturing.
3Reliability
If a shell is included in the helical strake design, then coating application for marine growth inhibition is improved, but manufacturing cost increases for moderate or low quantities
Solution Approach 1:
The shell is segmented from the complete helical strake assembly, allowing it to be manufactured separately using cost-effective methods appropriate for moderate or low quantities. The shell serves as the coating substrate for marine growth inhibition, while the segmentation enables flexible manufacturing choices. After the shell is coated and cured, fin elements are attached to the prepared openings, completing the assembly without requiring expensive complete molds.
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
This approach effectively reduces VIV by controlling vortex shedding and is cost-effective for moderate or low quantities, providing a durable solution for tubulars without the need for extensive mold production.
Implementation Method 1
A helical strake may include a shell with fins attached to the shell in a helical arrangement to disrupt the flow. Helical strakes control the point at which the oncoming current separates from the helical strake thereby controlling, and shortening, correlation length of the vortex shedding.
Data Source
AI summary
A helical strake for suppressing a vortex induced vibration (VIV) of a tubular. The helical strake having a shell dimensioned to at least partially encircle an underlying tubular, the shell having at least one fin opening; and at least one fin dimensioned to be positioned within the at least one fin opening formed by the shell, the at least one fin having a base portion dimensioned to be positioned along an underlying tubular and a tail portion dimensioned to extend through the at least one fin opening and radially outward from an underlying tubular.