Integrated Riblet Surface for Vehicle Drag Reduction

Solution Overview

Problem

Existing riblet structures for reducing turbulent flows on vehicle surfaces require separate dimensioning for different speed ranges and are often applied using adhesive foils, which can lead to mechanical weakness and loss of friction-reducing effectiveness.

Innovation Solution

A structural component with a riblet structure featuring a main channel and secondary channels branching off at angles greater than 0°, integrated directly into the surface, which can be produced using techniques like pulsed laser beams, providing increased mechanical strength and durability while maintaining the friction-reducing effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If riblet structures are applied using adhesive foils, then the friction-reducing effect is achieved, but the mechanical strength and durability are reduced

Engineering Contradiction:

Improvefriction lossVSAvoidmechanical strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The riblet structure is merged with the structural component surface itself, forming an integrated solution where the riblets are directly produced on the surface using laser pulses. This eliminates the need for separate adhesive foils and ensures the riblet structure becomes an inherent part of the component, thereby maintaining mechanical strength while achieving friction reduction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mechanical application method (adhesive foils) is replaced by a laser-based production method. The riblet structure is generated by scanning the surface with laser pulses, substituting the mechanical bonding approach with a direct surface modification technique that preserves the structural integrity of the component.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If riblet structures are applied using adhesive foils, then the friction-reducing effect is achieved, but the durability is reduced due to potential detachment

Engineering Contradiction:

Improvefriction lossVSAvoiddurability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The riblet structure is merged with the structural component surface itself, forming an integrated solution where the riblets are directly produced on the surface using laser pulses. This eliminates the need for separate adhesive foils and ensures the riblet structure becomes an inherent part of the component, thereby maintaining mechanical strength while achieving friction reduction.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If riblet structures are produced by laser scanning, then mechanical strength is increased, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidmanufacturing ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The mechanical application method (adhesive foils) is replaced by a laser-based production method. The riblet structure is generated by scanning the surface with laser pulses, substituting the mechanical bonding approach with a direct surface modification technique that preserves the structural integrity of the component.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Loss of energy

If riblets are designed for specific speed ranges, then the friction-reducing effectiveness is optimized, but adaptability across different vehicles is reduced

Engineering Contradiction:

Improvefriction lossVSAvoidadaptability

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The riblet dimensions are optimized for specific speed ranges by adjusting geometric parameters during the laser production process. The laser scanning method allows for precise control of riblet dimensions, enabling optimization for different velocity ranges while maintaining the same manufacturing process, thus balancing specialization with manufacturing versatility.

Inventive Principle:

Principle #35Parameter changes

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 reduces turbulent flows and enhances mechanical strength, preventing rounding or blunting of ribs, thus maintaining laminar flow and reducing surface resistance on aircraft and watercraft surfaces across varying speeds.

Implementation Method 1

The riblet structure is generated by scanning the surface with laser pulses

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The riblet structure is generated by scanning the surface with laser pulses

Methodology Applied

Scientific EffectLaser melting: Laser Beam Welding

Data Source

PatentEP2848823B1Structural component with a riblet surface

Publication Date: 2019.10.16 AIRBUS DEFENCE & SPACE GMBH

Figure 1A~2
Figure 3A~4

AI summary

A structural component for a vehicle is specified. The structural component has a surface (100) with a riblet structure (100), wherein the riblet structure has a plurality of grooves (110). The structural component is characterized in that a first groove (110) has a first longitudinal section (110A) which forms a first angle (112A) with a principal longitudinal direction (120) of the structural component, wherein the first angle (112A) is greater than 0° and wherein the principal longitudinal direction (120) corresponds to a flow direction of a fluid along the surface of the structural component.