Bionic Airfoil Surface for Low-Reynolds-Number Stall Reduction

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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, which can be manufactured using CAD/CAM data to create a bionic surface with protruding and recessed undulations for vortex flow enhancement.

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 performanceVSAvoidsurface geometry complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent copies the bionic surface geometry from dragonfly wings, which naturally exhibit superior aerodynamic performance at low Reynolds numbers. The method involves scanning a dragonfly wing to obtain point cloud data, processing it into a standardized surface model, and applying this bionic surface to the airfoil design, thereby transferring nature's optimized geometry to engineering application.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent transforms the complex bionic surface into manufacturable geometry by adjusting key parameters: simplifying the surface representation to a standardized model with controlled complexity, optimizing the distribution and density of control points, and refining the undulation characteristics to balance aerodynamic performance with manufacturing feasibility.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If bionic surface features are added 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 bionic surface is segmented into discrete control points and undulation zones along the airfoil surface. This segmentation allows the complex geometry to be broken down into manageable sections that can be independently manufactured and assembled, reducing overall manufacturing complexity while preserving the aerodynamic benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces adjustable undulation parameters that allow the bionic surface features to be dynamically tuned during manufacturing. This enables optimization of the surface geometry for different manufacturing methods (e.g., 3D printing, molding, composite layup) while maintaining the core bionic characteristics that improve aerodynamic performance.

Inventive Principle:

Principle #15Dynamics

3Reliability

If complex undulating surfaces are created, then vortex flow enhancement improves, but surface finish precision requirements increase

Engineering Contradiction:

Improvevortex flow controlVSAvoidsurface finish accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary processing of the bionic surface geometry by pre-calculating and pre-positioning control points and undulation patterns before manufacturing. This preliminary action ensures that the complex vortex-generating features are accurately defined in advance, reducing the precision requirements during actual manufacturing while maintaining effective vortex flow control.

Inventive Principle:

Principle #10Preliminary action

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

forming undulating surfaces inspired by dragonfly wings, which can be manufactured using CAD/CAM data to create a bionic surface with protruding and recessed undulations for vortex flow enhancement

Methodology Applied

Scientific EffectVortex flow: Vortex Ring

Data Source

PatentEP4610166A1An airfoil and adaptable wing with a bionic airfoil surface

Publication Date: 2025.09.03 AIRBUS OPERATIONS GMBH

Figure 1A~1D
Figure 1E~1F
Figure 2A~2B

AI summary

In order to improve aerodynamic properties and reduce the risk of stalling in the low speed Reynolds regime, the invention proposes a bionic derived airfoil (50) that includes in a mid portion between the leading edge and the trailing edge portions thereof a conventional surface portion (74) and a bionic surface portion (76). The conventional surface portion (74) is formed as a conventional airfoil surface. The bionic surface portion (76) is formed with a plurality of undulations (64) along a thickness direction. The conventional surface portion (74) and the bionic surface portion (76) are formed on opposite sides of the airfoil (50) along the thickness direction. An adaptable wing (88) includes two bionic airfoils (50) that are arranged such that their respecitve bionic surface portions (76) face each other and define a flow passage (94). A mechanism can move the bionic airfoils (50) relative to each other to adjust the size of the flow passage (94). The mechanism can close the bionic airfoils (50) so no flow passage (94) is present and a conventional airfoil (10) shape is formed.