Trawl Door Rib Configuration for Drag Reduction

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Solution Overview

Problem

Current trawl doors experience instability and high drag, leading to increased fuel consumption and turbulence, which negatively impacts fishing efficiency and marine species behavior.

Innovation Solution

A trawl door design featuring a dorsal and ventral face with a leading edge, trailing edge, upper edge, and lower edge, including three parallel ribs, where the trailing edge has converging sections and specific angle and length configurations to reduce drag and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional trawl door designs are used to maintain spreading power, then the panel stability is compromised, but if panel stability is improved through conventional means, then drag increases and turbulence worsens

Engineering Contradiction:
Improvepanel stabilityVSAvoiddrag
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The trailing edge of the panel is designed with a curved profile where the first midrib is set back from the upper and lower ribs, creating a hydrodynamic shape that reduces turbulence and drag while maintaining stability. This curvature allows water flow to detach more smoothly, reducing the turbulent wake and energy loss.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The panel structure uses different rib configurations at different locations: the first midrib extends only partway along the trailing edge while the second and third ribs extend to the edges. This local differentiation optimizes both stability (through the extended side ribs) and drag reduction (through the setback midrib creating favorable flow separation).

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If trawl doors are designed with conventional trailing edges, then spreading power is maintained, but turbulence increases and fuel consumption rises

Engineering Contradiction:
ImproveturbulenceVSAvoidfuel consumption
Core Design Contradiction:
Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The curved trailing edge profile with the setback first midrib creates a more streamlined shape that reduces turbulent wake. This hydrodynamic optimization directly reduces the energy required to tow the panel, lowering fuel consumption while maintaining the necessary spreading function.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If fishing time is extended to compensate for reduced fishing areas, then fishing efficiency decreases, but if fishing time is reduced, then spreading power and stability may be compromised

Engineering Contradiction:
Improvefishing efficiencyVSAvoidpanel stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The optimized trailing edge geometry improves panel stability through better hydrodynamic performance, allowing for shorter, more efficient fishing operations. The curved profile ensures consistent panel orientation and spacing, maintaining spreading power while reducing the need for extended fishing time to compensate for area limitations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design improves stability and reduces drag, minimizing turbulence and fuel consumption while maintaining effective spreading power, optimizing fishing operations and reducing environmental impact.

Implementation Method 1

The role of the two trawl doors 1 is to keep the bag properly open during fishing, thanks to the hydrodynamic effect related to the speed of water flow over the doors, their shape, and their angle of attack in the water.

Methodology Applied
Scientific EffectHydrodynamic effect: Drag

Data Source

PatentEP4424154A1Trawl door
Publication Date: 2024.09.04 ETAB MORGERE
  • EP4424154A1 patent drawingFigure 1
  • EP4424154A1 patent drawingFigure 2
  • EP4424154A1 patent drawingFigure 3

AI summary

The invention relates to a trawl door (1) comprising a dorsal face (10) and a ventral face (11) and delimited by a leading edge (12) and a trailing edge (13), as well as by an upper edge (14) and a lower edge (15), this door (1) being provided with at least three parallel ribs (16, 17, 18) and comprising a first median rib (16) extending from said leading edge (12) to said trailing edge (13), as well as a second upper rib (17) and a third lower rib (18), these second and third ribs (17, 18) being of identical length and mirror images of each other with respect to said first median rib (16), characterized in that the end (160) of said first median rib (16), on the side of said trailing edge (13), is set back from those (170,180) of the said upper and lower ribs (17,18).