Collapsible Fairing for Towed Line Strumming and Drag
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Solution Overview
Problem
Marine survey systems face inefficiencies due to drag and strumming issues caused by lines such as cables and ropes when towed behind a vessel, which reduce the effectiveness of seismic and electromagnetic surveys by increasing resistance and vibration.
Innovation Solution
A collapsible fairing is used to surround the lines, changing the hydrodynamic shape and reducing drag by extending and retracting without adding or removing sections, thereby minimizing strumming and drag when moving through water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lines such as cables and ropes are used to tow marine survey equipment, then the equipment can be deployed and retrieved, but drag and strumming increase reducing survey efficiency
Solution Approach 1:
A fairing is introduced as an intermediary component that surrounds the line. The fairing has a streamlined hydrodynamic shape that cuts through water more efficiently, reducing the drag force acting on the line and towed equipment while allowing the line to perform its deployment and retrieval function.
Solution Approach 2:
The fairing is designed with a curved, streamlined cross-sectional shape (such as an airfoil or teardrop shape) that is optimized for hydrodynamic flow. This curved geometry allows water to flow smoothly around the line, minimizing turbulence and vortex shedding, thereby reducing drag and energy loss during towing operations.
2Speed
If lines are pulled through water during towing, then equipment can be positioned and moved, but vortex shedding and strumming occur causing vibration and inefficiency
Solution Approach 1:
The fairing acts as a mediator between the line and the surrounding water. By providing a streamlined outer surface, it prevents direct interaction between the cylindrical line and water flow, thereby eliminating the conditions that generate vortex shedding and strumming while allowing the line to move freely for positioning and retrieval.
Solution Approach 2:
The streamlined curved shape of the fairing promotes smooth, laminar water flow around the line. This curvature prevents flow separation and vortex formation that would otherwise occur around the cylindrical line, significantly reducing vibration and strumming during towing at various speeds.
3Device complexity
If traditional cylindrical lines are used for towing, then the system is simple and cost-effective, but hydrodynamic efficiency is poor due to high drag
Solution Approach 1:
The fairing serves as an add-on intermediary component that can be attached to existing lines without replacing the entire line system. This approach maintains the simplicity and cost-effectiveness of using standard lines while dramatically improving hydrodynamic efficiency through the streamlined fairing geometry.
Solution Approach 2:
By applying a streamlined fairing with optimized curved cross-section to the cylindrical line, the overall hydrodynamic performance is improved without fundamentally changing the line system architecture. The fairing can be made from simple materials and attached using basic fastening methods, maintaining system simplicity while reducing drag.
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 collapsible fairing significantly reduces drag and vortex shedding, enhancing the efficiency of marine survey operations by maintaining a favorable hydrodynamic shape, allowing for smoother data collection with reduced resistance.
Implementation Method 1
A collapsible fairing is used to surround the lines, changing the hydrodynamic shape and reducing drag by extending and retracting without adding or removing sections, thereby minimizing strumming and drag when moving through water.
Implementation Method 2
The collapsible fairing significantly reduces drag and vortex shedding, enhancing the efficiency of marine survey operations by maintaining a favorable hydrodynamic shape
Data Source
AI summary
A system can include a float, a winch, a line, and a collapsible fairing. The winch can be coupled to the float. The line can be associated with the winch, where the winch is configured to extend and retract the line. The collapsible fairing can surround the line. Extension and retraction of the line can cause the collapsible fairing to extend and collapse.