Undulating Bionic Airfoil Surface for Low-Reynolds Flow Adaptation

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Solution Overview

Problem

Conventional airfoil designs struggle to achieve high aerodynamic performance in low Reynolds number regimes, such as those encountered in low density or small velocity conditions, particularly in environments like the Martian atmosphere.

Innovation Solution

The method involves generating airfoil manufacturing data by marking support points on a template airfoil, constructing connecting line segments without intersections, and forming undulating surfaces inspired by dragonfly wings to create a 'dragonized' airfoil with vortex-forming features, which can be manufactured using CAD/CAM data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional airfoil designs are used, then manufacturing simplicity is maintained, but aerodynamic performance in low Reynolds number regimes deteriorates

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidairfoil surface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The airfoil surface is segmented into multiple straight portions that form undulating portions, creating a bionic structure inspired by dragonfly wings. This segmentation allows the airfoil to generate vortices that improve aerodynamic performance in low Reynolds number regimes while maintaining a relatively simple manufacturing approach through defined geometric segments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The airfoil geometry parameters are changed by introducing undulating portions with specific straight segments that create vortex-forming features. The chordwise and spanwise positioning of these undulations modifies the flow characteristics to enhance performance at low Reynolds numbers without completely redesigning the entire airfoil structure

Inventive Principle:
Principle #35Parameter changes

2Reliability

If bionic undulating surfaces are introduced to improve low Reynolds number performance, then aerodynamic efficiency increases, but manufacturing complexity increases

Engineering Contradiction:
Improvelift-to-drag ratioVSAvoidmanufacturing process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The complex bionic surface is divided into multiple straight portions that can be independently defined and manufactured. Each straight portion connects to form undulating patterns, allowing the complex geometry to be broken down into manufacturable segments that can be produced using standard aerospace manufacturing techniques

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The undulating portions are formed by connecting straight line segments at specific angles, creating a piecewise linear approximation of curved bionic surfaces. This approach maintains the vortex-generating capability while simplifying manufacturing compared to complex continuous curves

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Manufacturing precision

If support points are densely distributed to accurately capture airfoil geometry, then manufacturing precision improves, but data processing complexity increases

Engineering Contradiction:
Improveairfoil geometry accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using densely distributed support points to define the entire airfoil surface, the method segments the geometry into key support points that define straight portions. These segments connect to form the complete undulating surface, reducing the number of data points needed while maintaining manufacturing precision through the defined geometric relationships between segments

Inventive Principle:
Principle #1Segmentation

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 derived airfoils exhibit improved aerodynamic performance and mechanical stability, reducing the risk of stalling and enhancing lift-to-drag ratios, especially in low Reynolds number conditions.

Implementation Method 1

The undulating portions (64) allow formation of a vortex (114) which acts as a storage for mechanical energy

Methodology Applied
Scientific EffectVortex formation: Vortex Ring

Data Source

PatentEP4610168A1An adaptable airfoil for wing with a bionic airfoil surface
Publication Date: 2025.09.03 AIRBUS OPERATIONS GMBH
  • EP4610168A1 patent drawingFigure 1A~1D
  • EP4610168A1 patent drawingFigure 1E~1F
  • EP4610168A1 patent drawingFigure 2A~2B

AI summary

In order to improve aerodynamic performance in the low speed Reynolds regime, the invention proposes an airfoil (50) that includes a plurality of straight portions (70, 72) that form a plurality of undulating portions (64) that undulate along a thickness direction, when viewed along a spanwise direction. The undulations (64) allow formation of a vortex (114) that acts as a storage for mechanical energy. The undulations (64) allow bending and thereby adaption of the airfoil (50) to the current airflow. The vortex (114) can be energized actively, thereby reducing the risk of stalling at low Reynolds speeds.